McqMate
| 101. |
Cement is made hard with – |
| A. | dehydration |
| B. | hydration and dissociation of water |
| C. | Dissociation of water |
| D. | Polymerisation |
| Answer» B. hydration and dissociation of water | |
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Explanation: Cements (e.g., Portland cement) harden because of hydration, chemical reactions that occur independently of the mixture's water content; they can harden even underwater or when constantly exposed to wet weather. The chemical reaction that results when the anhydrous cement powder is mixed with water produces hydrates that are not water - soluble. |
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| 102. |
Which of the following gas leaked in the Bhopal Gas tragedy in December 1984? |
| A. | Methyl isocyanate |
| B. | Methyl isochlorate |
| C. | Methyl phosphate |
| D. | Methyl isopropate |
| Answer» A. Methyl isocyanate | |
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Explanation: In the gas tragedy that occurred at the Union Carbide India Limited pesticide plant in Bhopal, Madhya Pradesh, on 2-3 December 1984. |
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| 103. |
Which acid is used in rubber, textile, leather and electroplating industries? |
| A. | Ethanoic acid |
| B. | Methanoic acid |
| C. | Malanic acid |
| D. | Butairic acid |
| Answer» B. Methanoic acid | |
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Explanation: 0 |
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| 104. |
Study of Fossils is known as? |
| A. | Paleontology |
| B. | Petrology |
| C. | Seismology |
| D. | None of the above |
| Answer» A. Paleontology | |
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Explanation: Paleontology is the study of the history of life on Earth as based on fossils. Fossils are the remains of plants, animals, fungi, bacteria, and single-celled living things that have been replaced by rock material or impressions of organisms preserved in rock. |
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| 105. |
A substance which readily forms colloidal solution in contact with water is called – |
| A. | Extrinsic colloid |
| B. | Associated colloid |
| C. | Hydrophobic colloid |
| D. | Hydrophilic colloid |
| Answer» D. Hydrophilic colloid | |
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Explanation: A colloidal dispersion in which the dispersed particles are more or less liquid and exert a certain attraction on and absorb a. certain quantity of the fluid in which they are suspended is called as hydrophilic colloid. Molecules of a hydrophilic colloid have an affinity for water molecules and when dispersed in water become hydrated. Hydrated colloids swell and increase the viscosity of the system,thereby improving stability by reducing the interaction between particles and their tendency to settle. They may also possess a net surface electrical charge. |
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| 106. |
Denatured spirit is ethanol mixed with |
| A. | Petrol |
| B. | Kerosene |
| C. | Water |
| D. | Pyridine |
| Answer» D. Pyridine | |
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Explanation: Denatured alcohol or methylated spirits is ethanol that has additives to make it undrinkable (poisonous), to discourage recreational consumption. In some cases it is also dyed. Denatured alcohol is used as a solvent and as fuel for spirit burners and camping stoves. Because of the diversity of industrial uses for denatured alcohol, hundreds of additives and denaturing methods have been used. |
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| 107. |
The most abundant inert gas in the atmosphere is – |
| A. | Helium |
| B. | Neon |
| C. | Argon |
| D. | Krypton |
| Answer» C. Argon | |
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Explanation: Argon is the third most common gas in the Earth's atmosphere, at 0.93% (9,300 ppm), making it approximately 23.8 times as abundant as new most common atmospheric gas, carbon dioxide (390 ppm), and more than 500 times as abundant as the next most common noble gas, neon (18 ppm). Nearly all of this argon is radiogenic argon-40 derived from the decay. of potassium-40 in the Earth's crust. |
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| 108. |
Nuclear energy is a mineral-based energy source. It is derived from – |
| A. | uranium |
| B. | thorium |
| C. | plutonium |
| D. | All tithe above |
| Answer» A. uranium | |
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Explanation: The sun and stars are seemingly inexhaustible sources of energy. That energy is the result of nuclear reactions, in which matter is converted to energy. We have been able to harness that mechanism and regularly use it to generate power. Presently, nuclear energy provides for approximately 16% of the world's electricity. Unlike the stars, the nuclear reactors that we have today work on the principle of nuclear fission. |
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| 109. |
Zinc sulphide is commonly used as – |
| A. | fungicide |
| B. | herbicide |
| C. | rodenticide |
| D. | deodorant |
| Answer» C. rodenticide | |
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Explanation: Rodenticides are a category of pest control chemicals intended to kill rodents. Metal phosphides have been used as a means of killing rodents and are considered single-dose fast acting rodenticides (death occurs commonly within 1-3 days after single bait ingestion). A bait consisting of food and a phosphide (usually zinc phosphide) is left where the rodents can eat it. The acid in the digestive system of the rodent reacts with the phosphide to generate the toxic phosphine gas. |
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| 110. |
Galena is a mineral of – |
| A. | iron |
| B. | gold |
| C. | lead |
| D. | calcium |
| Answer» C. lead | |
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Explanation: Galena is the natural mineral form of lead (II) sulfide. It is the most important lead ore mineral. Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite. Galena deposits often contain significant amounts of silver as included silver sulfide mineral phases or as limited solid solution within the galena structure. |
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| 111. |
Magnalium is an alloy of – |
| A. | Aluminium and Magnesium |
| B. | Magnesium and Tin |
| C. | Aluminium and Zinc |
| D. | Manganese and Magnesium |
| Answer» A. Aluminium and Magnesium | |
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Explanation: MagnaHum is an aluminium alloy with 1.5 to 2% magnesium and small amounts of copper, nickel, and tin. Some alloys, intended for particular uses at the cost of poor corrosion resistance, may consist of up to 50% magnesium. It finds use in engineering and pyrotechnics. Alloys with smaller amounts of magnesium (about 5%) exhibit greater strength, greater corrosion resistance, and lower density than pure aluminium. |
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| 112. |
Which of the toxic heavy metals is found in modern tannery industries? |
| A. | Nickel |
| B. | Zine |
| C. | Chromium |
| D. | Lead |
| Answer» C. Chromium | |
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Explanation: Chromium is mainly found in waste from the chrome tanning process; it occurs as part of the retanning system and is displaced from leathers during retanning and dyeing processes. This chrome is discharged from processes in soluble form; however, when mixed with tannery waste waters from other processes (especially if proteins are present), the reaction is very rapid. Precipitates are formed, mainly proteinchrome, which add to sludge generation. |
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| 113. |
Which of the following contains high content of lead? |
| A. | Coal |
| B. | Cooking gas |
| C. | High octane fuel |
| D. | Low octane fuel |
| Answer» C. High octane fuel | |
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Explanation: A high-octane-rated fuel, such gasoline contains lead. Straight-run gasoline isdistilled directly from crude oil. Once the leading source of fuel, its low octane rating required lead additives. Most countries have phased out leaded fuel. Different additives have replaced the lead compounds. The most popular additives include aromatic hydrocarbons, ethers and alcohol (usually ethanol or methanol). Lead used to be added to petrol and this was the source of high levels of lead in the air. |
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| 114. |
Acids on reacting with metals release which of the following gases? |
| A. | Oxygen |
| B. | Carbon Dioxide |
| C. | Hydrogen |
| D. | Methane |
| Answer» C. Hydrogen | |
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Explanation: Acids on reacting with some reactive metals result in the formation of a salt and hydrogen gas. The general equation that describes the chemical reaction between an acid and metal is Metal + acid = salt + hydrogen gas. |
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| 115. |
Carbon reacts with metal to form - |
| A. | Carbide |
| B. | Carbonate |
| C. | Hydroxide |
| D. | Oxide |
| Answer» A. Carbide | |
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Explanation: Carbon reacts with reactive metals, such as tungsten, carbon forms either carbides to form alloys with high melting points. |
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| 116. |
Radioactive disintegration of Uranium ultimately results in formation of - |
| A. | Radium |
| B. | Thorium |
| C. | Polonium |
| D. | Lead |
| Answer» D. Lead | |
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Explanation: Radioactive decay (also known as nuclear decay, radioactivity or nuclear radiation) is the process by which an unstable atomic nucleus loses energy (in terms of mass in its rest frame) by emitting radiation |
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| 117. |
Energy use in solar cookers, solar distillation plants, solar power plants is known as – |
| A. | chemical energy |
| B. | solar energy |
| C. | thermal energy |
| D. | nuclear energy |
| Answer» B. solar energy | |
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Explanation: Solar energy is radiant light and heat from the Sun that is harnessed using a range of ever-evolving technologies such as solar heating, solar thermal energy, solar architecture, molten salt power plants and artificial photosynthesis. |
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| 118. |
'Vinegar' is a commercial name of – |
| A. | Oxalic acid |
| B. | Hydrochloric acid |
| C. | Acetic acid |
| D. | Citric acid |
| Answer» C. Acetic acid | |
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Explanation: Vinegar is a liquid substance consisting mainly of acetic acid (CH3CO2H) and water, the acetic acid being produced through the fermentation of ethanol by acetic acid bacteria. It is today mainly used in the kitchen as a general cooking ingredient. |
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| 119. |
Which metal does not undergo corrosion due to the formation of oxide layer? |
| A. | Copper |
| B. | Iron |
| C. | Aluminium |
| D. | Zinc |
| Answer» C. Aluminium | |
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Explanation: Corrosion is an oxidation reaction with atmospheric oxygen in the presence of water on the surface of a metal. Iron corrodes more quickly than most other transition metals to form an iron oxide. Aluminium also undergoes an oxidation reaction, but does not oxidize and corrode as quickly as its reactivity suggests. Once a thin oxide layer of Al2O3 has formed on the surface, it forms a barrier tooxygen and water to prevent further corrosion of the aluminium. |
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| 120. |
The acid present in red ants is – |
| A. | Acetic acid |
| B. | Butyric acid |
| C. | Caproic acid |
| D. | Formic acid |
| Answer» D. Formic acid | |
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Explanation: Formic acid is the simplest carboxylic acid. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant. Formica, referring to its early isolation by the distillation of ant bodies. |
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| 121. |
The metal extracted from Bauxite is – |
| A. | Silver |
| B. | Copper |
| C. | Manganese |
| D. | Aluminum |
| Answer» D. Aluminum | |
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Explanation: Bauxite is an aluminium ore and is the main source of aluminium. Approximately 70% to 80% of the world's dry bauxite production is processed first into alumina, and then into aluminium by electrolysis as of 2010. Usually, bauxite ore is heated in a pressure vessel along with a sodium hydroxide solution at a temperature of 150 to 200 °C. At these temperatures, the aluminium is dissolved as an aluminate (the Bayer process). |
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| 122. |
pH value between 6.5-7.5 makes the soil |
| A. | Basic |
| B. | Neutral |
| C. | Acidic |
| D. | None of these |
| Answer» D. None of these | |
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Explanation: In chemistry, pH is a measure of the activity of the (solvated) hydrogen ion. P [H], which measures the hydrogen ion concentration is closely related to, and is often written as, pH. Pure water has a pH very close to 7 at 25°C. Solutions with a pH less than 7 aresaid to be acidic and solutions with a pH greater than 7 are basic or alkaline. A pH of 7 is treated as neutral. |
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| 123. |
The metal chiefly used for galvanizing iron is: |
| A. | Zine |
| B. | Mercury |
| C. | Cadmium |
| D. | Tin |
| Answer» A. Zine | |
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Explanation: Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting. In current use, the term refers to the coating of steel or iron with zinc. This is done to prevent rusting of the ferrous item. The value of galvanizing stems from the corrosion resistance of zinc, which, under most service conditions, is considerably greater than that of iron and steel. |
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| 124. |
Submarines move under water. They have engines that run on - |
| A. | Petrol and oxygen |
| B. | Diesel |
| C. | Batteries |
| D. | Steam |
| Answer» B. Diesel | |
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Explanation: Early submarines used a direct mechanical connection between the engine and propeller, switching between diesel engines for surface running, and electric motors for submerged propulsion. Dieselelectric submarines have a stealth advantage over their nuclear Counterparts. |
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| 125. |
The Bhopal gas tragedy was caused by the gas - |
| A. | Methyl chloride |
| B. | Methyl Iso Cyanide |
| C. | Methyl Iso Cyanate |
| D. | Methyl Cyanide |
| Answer» C. Methyl Iso Cyanate | |
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Explanation: The Bhopal disaster occurred on the night of 2-3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant inBhopal, Madhya Pradesh. Over 500,000 people were exposed to methyl isocyanate has and other chemicals. The toxic substance made its way in and around the shantytowns located near the plant. |
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| 126. |
The wine is prepared by the process of |
| A. | fermentation |
| B. | catalysation |
| C. | conjugation |
| D. | displacement |
| Answer» A. fermentation | |
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Explanation: After the destemmer the wine is pumped into tanks to begin fermentation. The process of fermentation in winemaking turns grape juice into an alcoholic beverage. |
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| 127. |
Fission and fusion are called - |
| A. | molecular reactions |
| B. | potential reactions |
| C. | nuclear reactions |
| D. | heat reactions |
| Answer» C. nuclear reactions | |
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Explanation: The energy harnessed in nuclei is released in nuclear reactions. Fission is the splitting of a heavy nucleus into lighter nuclei and fusion is the combining of nuclei to form a bigger and heavier nucleus. Fission and fusion are called nuclear reactions |
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| 128. |
Acids on reacting with metal carbonates release which of the following gases? |
| A. | Hydrogen sulphide |
| B. | Carbon Dioxide |
| C. | Propane |
| D. | Hydrogen |
| Answer» B. Carbon Dioxide | |
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Explanation: When an acid reacts with a metal carbonate, a salt, water and carbon dioxide are produced: Acid + metal carbonate → salt + water + carbon dioxide |
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| 129. |
Which of the following is released during photosynthesis? |
| A. | Oxygen |
| B. | Carbon dioxide |
| C. | Energy |
| D. | Light |
| Answer» A. Oxygen | |
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Explanation: Plants use photosynthesis as a way of producing glucose. They take in light energy from the sun and water and carbon dioxide from the air. This is then used to produce oxygen and glucose. 6CO2 + 6 H2O → C6H12O6 + 6O2 |
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| 130. |
Who discovered electron? |
| A. | E. Goldstien |
| B. | J. J. Thomson |
| C. | Ernest Rutherford |
| D. | J. Chadwick |
| Answer» B. J. J. Thomson | |
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Explanation: J.J. Thomson is credited with the discovery and identification of the electron. Thomson, in 1897, was the first to suggest that one of the fundamental units was more than 1,000 times smaller than an atom, suggesting the sub atomic particle now known as the electron. |
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| 131. |
Which of the following is also known as Carbolic Acid? |
| A. | Phenol |
| B. | Hydroxide |
| C. | Sulphuric Acid |
| D. | Ethanol |
| Answer» A. Phenol | |
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Explanation: Phenol is also known ascarbolic acid. It is an aromatic organic. |
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| 132. |
Galvanization of iron is carried out using – |
| A. | Zinc |
| B. | Tin |
| C. | Copper |
| D. | Chromium |
| Answer» A. Zinc | |
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Explanation: Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting. The term is derived from the name of Italian scientist Luigi Galvani. Although galvanization can be done with electrochemical and electrodeposition processes, the most common method in current use is hot-dip galvanization, in which steel parts are submerged in a bath of molten zinc. |
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| 133. |
Cokking gas is a mixture of - |
| A. | methane and ethylene |
| B. | carbon dioxide and oxygen |
| C. | butane and propane |
| D. | carbon monoxide and carbon dioxide |
| Answer» C. butane and propane | |
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Explanation: Liquefied petroleum gas, also called LPG, GPL, LP Gas, liquid petroleum gas or simply propane or butane, is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. When specifically used as a vehicle fuel it is often referred to as autogas. |
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| 134. |
The purest form of water is – |
| A. | tap water |
| B. | rain water |
| C. | ground water |
| D. | distilled water |
| Answer» B. rain water | |
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Explanation: Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then precipitated—that is, become heavy enough to fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides suitable conditions for many types of ecosystem, as well as water for hydroelectric power plants and crop irrigation. The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. |
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| 135. |
The main constituent of biogas is – |
| A. | oxygen |
| B. | methane |
| C. | acetic acid |
| D. | methyl alcohol |
| Answer» B. methane | |
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Explanation: Biogas typically refers to a gas produced by breakdown of organic matter in the absence of oxygen. Organic waste such as dead plant and animal material, animal feces, and kitchen waste can be converted into a gaseous fuel called biogas. Biogas originates from biogenic material and is a type of bio fuel. Biogas is produced by the anaerobic digestion or fermentation of biodegradable materials such as biomass, manure, sewage, municipal waste, green waste, plant material, and crops. |
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| 136. |
Which metal is extracted from sea water? |
| A. | Potassium |
| B. | Magnesium |
| C. | Aluminium |
| D. | Beryllium |
| Answer» B. Magnesium | |
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Explanation: The metal is now mainly obtained by electrolysis of magnesium salts obtained from brine. Commercially, the chief use for the metal is as an alloying agent to make aluminium- magnesium alloys, sometimes called "magnalium" or "magnelium". Since magnesium is less dense than aluminium, these alloys are prized for their relative lightness and strength. Magnesium is the fourth most common element in the Earth as a whole (behind iron, oxygen and silicon), making up 13% of the planet's mass and a large fraction of the planet's mantle. |
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| 137. |
Percentage of lead in lead pencils is – |
| A. | "0" |
| B. | 31-66 |
| C. | 40 |
| D. | 80 |
| Answer» A. "0" | |
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Explanation: There is no lead in pencils. Rather, the core is made up of non-toxic mineral called graphite. The common name "pencil lead" is due to an historic association with the stylus made of lead in ancient Roman times. Most pencil cores are made of graphite mixed with a clay binder, leaving grey or black marks that can be easily erased. Graphite pencils are used for both writing and drawing, and the result is durable: although writing can usually be removed with an eraser, it is resistant to moisture, most chemicals, ultraviolet radiation and natural aging. |
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| 138. |
When formaldehyde and potassium hydroxide are heated, we get – |
| A. | Acetylene |
| B. | Methyl alcohol |
| C. | Methane |
| D. | Ethyl formate |
| Answer» B. Methyl alcohol | |
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Explanation: When formaldehyde and potassium hydroxide are heated,we get methyl alcohol and formic acid. it is cannizarroo reaction. The Cannizzaro reaction, named after its discoverer StanislaoCannizzaro, is a chemical reaction that involves the base-induced disproportionation of an aldehyde. Cannizzaro first accomplished this transformation in 1853, when he obtained benzyl alcohol and potassium benzoate from the treatment of benzaldehyde with potash (potassium carbonate). |
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| 139. |
When conc. H2SO4 is added to diy KNO3, brown fumes are evolved. These fumes are due to – |
| A. | SO3 |
| B. | SO2 |
| C. | NO2 |
| D. | N2O |
| Answer» C. NO2 | |
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Explanation: when concentrated hydrosulphuric acid is added to dry potassium nitrate brown fumes are evolved and these fumes are evolved due to the formation of nitrogen dioxide. Nitrogen dioxide is the chemical compound with the formula NO2. It is one of several nitrogen oxides. NO2 is an intermediatein the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odour and is a prominent air pollutant. Nitrogen dioxide is a paramagnetic and bent molecule. |
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| 140. |
Pasteurisation of milk means – |
| A. | heating of milk to above 72°C |
| B. | heating of milk to above 62°C |
| C. | cooling of milk to about 62°C |
| D. | cooling of milk to about 10°C |
| Answer» B. heating of milk to above 62°C | |
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Explanation: Pasteurization typically uses temperatures below boiling, since at very high temperatures, casein micelles will irreversibly aggregate, or "Curdle". The two main types of pastemization used today are: high-temperature, short-time (HTST) and "extended shelf life" (ESL) treatment. Ultra-high temperature (UHT or ultra-heat-treated) is also used for milk treatment. |
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| 141. |
Aluminium can be purified by – |
| A. | oxidation |
| B. | distillation |
| C. | electrolysis |
| D. | ozonolysis |
| Answer» C. electrolysis | |
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Explanation: Electrolysis is a method of using a direct electric current (DC) to drive an otherwise non-spontaneous chemicaireaction. Electrolysis is commercially highly important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. Aluminum is extracted from its oxide ore "Bauxite". |
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| 142. |
Which among the following elements is found in maximum percentage in the human body? |
| A. | Carbon |
| B. | Hydrogen |
| C. | Nitrozen |
| D. | Oxyzen |
| Answer» D. Oxyzen | |
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Explanation: Most of the human body is made up of water, H2O, with cells consisting of 65- 90% water by weight. Therefore, it isn't surprising that most of a human body's mass is oxygen. Carbon, the basic unit for organic molecules, comes in second. 99% of the mass of the human body is made up of just six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. |
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| 143. |
Which of the following acids is present in sour milk? |
| A. | Formic acid |
| B. | Lactic acid |
| C. | Citric acid |
| D. | Tartaric acid |
| Answer» B. Lactic acid | |
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Explanation: Sour Tasting milk products, like yogurt, butter milk, etc developed sour taste as milk is cultured with lactic acid bacteria. |
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| 144. |
Non-metallic oxides are in nature. |
| A. | Basic |
| B. | Acidic |
| C. | Neutral |
| D. | None of the above |
| Answer» B. Acidic | |
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Explanation: Reaction between a non-metallic oxide and an acid leads to the formation of a salt and water. This is similar to the reaction between a base and an acid; we can conclude that nonmetallic oxides are acidic in nature. |
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| 145. |
Detergents used for cleaning clothes and utensils contain – |
| A. | nitrates |
| B. | bicarbonates |
| C. | sulphonates |
| D. | bismuthates |
| Answer» C. sulphonates | |
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Explanation: Sulphonate is a detergent used for cleaning clothes and utensils. It is a salt or ester of any sulphonic acid. |
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| 146. |
Radioactive disintegration of uranium ultimately results in formation of – |
| A. | radium |
| B. | thorium |
| C. | polonium |
| D. | lead |
| Answer» D. lead | |
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Explanation: Uranium-lead (U-Pb) dating is one of the oldest and most refined of the radiometric dating schemes, with a routine age range of about 1 million years to over 4.5 billion years, and with routine precisions in the 0.1-1 percent range. |
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| 147. |
Impure camphor is purified by – |
| A. | sublimation |
| B. | fractional crystallisation |
| C. | fractional distillation |
| D. | steam distillation |
| Answer» A. sublimation | |
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Explanation: Sublimation apparatus is a piece of laboratory glassware used in the technique of sublimation usually used by chemists to purify compounds. Typically a solid is placed in a vessel which is then heated under vacuum. Under this reduced pressure the solid volatilizes and condenses as a purified compound on a cooled surface, leaving the non-volatile residue impurities behind. This cooled surface often takes the form of a cold finger. Once heating ceases and the vacuum is released, the sublimed compound can be collected from the cooled surface. Impure camphor is purified by this process. |
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| 148. |
Which among the following stage is suitable indicator when solution of sodium carbonate is mixed with sulphuric acid? |
| A. | Methylene blue |
| B. | Methyl red |
| C. | Phenolphthaline |
| D. | Methyl orange |
| Answer» D. Methyl orange | |
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Explanation: Methyl orange is a pH indicator frequently used in titrations. It is often used in titrations because of its clear and distinct colour change. Because it changes colour at the pH of a mid-strength acid, it is usually used in titrations for acids. |
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| 149. |
In which of the following states maximum iron are is found? |
| A. | FeCO3 |
| B. | Fe2O3 |
| C. | Fe3O4 |
| D. | FeS2 |
| Answer» B. Fe2O3 | |
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Explanation: Iron ores are rocks and minerals from which metallic iron can be economically extracted. The iron itself is usually found in the form of magnetite (Fe3O4), hematite (Fe2O3), goethite (FeO(OH), limonite (FeO(OH).n(H2O)) or siderite (FeCO3). Hematite, also spelled as haematite, is the mineral form of iron(III) oxide (Fe2O3), one of several iron oxides. It is mined as the main ore of iron. Huge deposits of hematite are found in banded iron formations. Gray hematite is typically found in places where there has been standing water or mineral hot springs, such as those in Yellowstone National Park in the United States. |
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| 150. |
Greenhouse effect is caused by – |
| A. | nitrogen |
| B. | carbon dioxide |
| C. | carbon monoxide |
| D. | nitrogen dioxide |
| Answer» B. carbon dioxide | |
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Explanation: The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. By their percentage contribution to the d effect on Earth the four major gases are: water vapor, 36-70%, carbon dioxide, 9- 26%, methane, 4-9% and ozone, 3-7%. |
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| 151. |
The polymer used in making plastic crockery is – |
| A. | Decron |
| B. | Nylon |
| C. | Bakelite |
| D. | Melamine |
| Answer» D. Melamine | |
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Explanation: Melamine-formaldehyde resin or melamine is used in the manufacture of plastic crockery. Melamine resin or melamine formaldehyde (also shortened to melamine) is a:hard, thermosetting plastic material made from melamine and formaldehyde by polymerization. Melamine resin is often used in kitchen utensils and plates (such as Melmac). Melamine resin utensils and bowls are not microwave safe. As with all thermosetting materials, melamine resin cannot be melted and, therefore, cannot be recycled through melting. |
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| 152. |
Vulcanization of rubber is carried out by adding – |
| A. | Sulphur |
| B. | Carbon |
| C. | Ozone |
| D. | Phosphorus |
| Answer» A. Sulphur | |
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Explanation: Vulcanization is a chemical process for converting rubber or related polymers into more durable materials via the addition of sulfur or other equivalent "curatives" or "accelerators". These additives modify the polymer by forming crosslinks (bridges) between individual polymer chains. Vulcanized |
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| 153. |
Helium gas is used in gas balloons instead of hydrogen gas be-cause it is – |
| A. | lighter than hydrogen |
| B. | more abundant than hydrogen |
| C. | non-combustible |
| D. | more stable |
| Answer» C. non-combustible | |
|
Explanation: Because of the Archimedes' principle, a lifting gas is required for aerostats to create buoyancy. Its density is lower than that of air (about 1.29 kg/m3, 1.29 g/L). Only certain lighter than air gases are suitable as lifting gases. Hydrogen and helium are the most commonly used lift gases. Although helium is twice as heavy as (diatomic) hydrogen, they are both so much lighter than air that this difference is inconsequential. Both provide about 9.8 N of lift (1 Newton is the force required to accelerate 1 kg at 1 misec2) per cubic meter of gas at STP. |
|
| 154. |
Aspirin is chemically known as – |
| A. | methyl salicylate |
| B. | hydroxysalicylate |
| C. | acetylsalicylic acid |
| D. | alkylsalicylic acid |
| Answer» C. acetylsalicylic acid | |
|
Explanation: Aspirin (USAN), also known as acetylsalicylic acid, is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. Salicylic acid, the main metabolite of aspirin, is an integral part of human and animal metabolism. While in humans much of it is attributable to diet, a substantial part is synthesized endogenously. |
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| 155. |
The most abundant element in the human body is – |
| A. | carbon |
| B. | iron |
| C. | nitrogen |
| D. | oxygen |
| Answer» D. oxygen | |
|
Explanation: The composition of the human body can be looked at from the point of view of either mass composition, or atomic composition. To illustrate both views, the human body is 70% water, and water is 11% hydrogen by mass but 67% hydrogen by atomic percent. Thus, most of the mass of the human body is oxygen, but most of the atoms in the human body are hydrogen atoms. |
|
| 156. |
Dry powder fire extinguishers contain - |
| A. | sand |
| B. | sand and sodium carbonate |
| C. | sand and potassium carbonate |
| D. | sand and sodium bicarbonate |
| Answer» D. sand and sodium bicarbonate | |
|
Explanation: Dry chemical is a powder based agent that extinguishes by separating the four parts of the fire tetrahedron. It prevents the chemical reactions involving heat, fuel, and oxygen and halts the production of fire sustaining "free-radicals", thus extinguishing the fire. Sodium bicarbonate, "regular" or "ordinary" used on class B and C fires, was the first of the thy chemical agents developed. In the heat of a fire, it releases a cloud of carbon dioxide that smothers the fire. |
|
| 157. |
Which type of glass is used for making glass reinforced plastic? |
| A. | Pyrex glass |
| B. | Flint glass |
| C. | Quartz glass |
| D. | Fibre glass |
| Answer» D. Fibre glass | |
|
Explanation: Fiberglass is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK. Fiberglass is a lightweight, extremely strong, and robust material. Although strength properties are somewhat lower than carbon fiber and it is less stiff, the material is typically far less brittle, and the raw materials are much less expensive. Its bulk strength and weight properties are also very favorable whencompared to metals, and it can be easily formed using molding processes. |
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| 158. |
Who invented radar? |
| A. | Fred Morrison |
| B. | A H Taylor and Leo C Young |
| C. | Van Tassel |
| D. | W. K. Roentgen |
| Answer» B. A H Taylor and Leo C Young | |
|
Explanation: Like many inventions, that of radar is difficult to ascribe to an individual. Robert Watson-Watt is given the credit for inventing the radar. However Albert H. Taylor and Leo C Young at the U.S. |
|
| 159. |
In which following processes light energy is converted into chemical energy? |
| A. | Respiration |
| B. | Fermentation |
| C. | Photosynthesis |
| D. | Photorespiration |
| Answer» C. Photosynthesis | |
|
Explanation: Photosynthesis is the process by which plants, some bacteria and some protestants use the energy from sunlight to produce glucose from carbon dioxide and water. |
|
| 160. |
What is the common characteristic of the elements of the same group in the periodic table? |
| A. | Electrons in outer most shell |
| B. | Total number of electrons |
| C. | Total number of protons |
| D. | Atomic weight |
| Answer» A. Electrons in outer most shell | |
|
Explanation: Elements in the same group in the periodic table have similar chemical properties. This is because their atoms have the same number of electrons in the outer orbital. |
|
| 161. |
The fiber least prone to catch fire is – |
| A. | nylon |
| B. | polyester |
| C. | cotton |
| D. | terylene |
| Answer» C. cotton | |
|
Explanation: The fiber least prone to catch fire is cotton. Besides, in cases of fire due to electricity, cotton is less prone to static electricity buildup than nylon or other synthetics. Cotton and wool are naturally less prone to burning because the fire can be smothered in the thick fibers. |
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| 162. |
Which of the following hormone is called emergency hormone? |
| A. | Insulin |
| B. | Adrenaline |
| C. | Oestrogen |
| D. | Oxytocir |
| Answer» B. Adrenaline | |
|
Explanation: Adrenaline increases the heart beat and breathing rate which results in the supply of more oxygen to muscles. It reduces the blood to the digestive system and skin; as a result the blood further reaches the skeletal muscles. |
|
| 163. |
Polythene is industrially prepared by the polymerization of - |
| A. | Methane |
| B. | Styrene |
| C. | Acetylene |
| D. | Ethylene |
| Answer» D. Ethylene | |
|
Explanation: Ethylene is a small hydrocarbon gas. It is naturally occurring, but it can also occur as a result of combustion and other processes. |
|
| 164. |
Molasses a by-product in the manufacture of sugar, is converted into - |
| A. | alcohol |
| B. | paper |
| C. | fuel |
| D. | pulp |
| Answer» A. alcohol | |
|
Explanation: Molasses are the principal ingredient in the distillation of rum. Rum is therefore common in regions of the world where sugarcane or sugar beets are heavily cultivated. It is used in the manufacture of ethyl alcohol for industry and as an ingredient in cattle feed. |
|
| 165. |
The wire of flash bulb is made of : |
| A. | Copper |
| B. | Barium |
| C. | Magnesium |
| D. | Silver |
| Answer» C. Magnesium | |
|
Explanation: The first modern photoflash bulb (or flashbulb) was made by Austrian Paul Vierkotter, who used magnesium coated wire in an evacuated glass globe. It was later determined that aluminum foil in a low pressure oxygen atmosphere worked even better, and was cheaper to produce. |
|
| 166. |
The coloured discharge tubes for advertisement mainly contain - |
| A. | Xenon |
| B. | Argon |
| C. | Helium |
| D. | Neon |
| Answer» D. Neon | |
|
Explanation: Neon gives a distinct reddish- orange glow when used in either low-voltage neon glow lamps or in highvoltage discharge tubes or neon advertising signs. The red emission line from neon is also responsible for the well known red light of helium-neon lasers. Neon is used in a few plasma tube and refrigerant applications but has few other commercial uses. |
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| 167. |
Muscle fatigueisaccumulation of : (1) Pyruvic acid(2) Lactic acid(3) Oxalacetic acid(4) Uric acidQ.30) A mixture of water and alcohol can be separated by - |
| A. | Filtration |
| B. | Evaporation |
| C. | Distillation |
| D. | Decantation |
| Answer» C. Distillation | |
|
Explanation: Simple distillation is a procedure by which two liquids with different boiling points can be separated. |
|
| 168. |
Setting of plaster of paris involves – |
| A. | dehydration process |
| B. | hydration to form other hydrates |
| C. | oxidation process |
| D. | reduction process |
| Answer» B. hydration to form other hydrates | |
|
Explanation: The setting of plaster of Paris takes place by hydration due to the formation of a solid crystalline hydrate and hardening of Plaster of Paris is hydration reaction, which is reverse of the dehydration of gypsum. Plaster of Paris quickly sets to a hard mass when made into a thin paste with water. A slight expansion takes place in the process and heat is evolved. This process is exothermic. |
|
| 169. |
The common name for the com-pound having formal NaOH is – |
| A. | Caustic soda |
| B. | Caustic potash |
| C. | Soda ash |
| D. | Sodium hydroxide |
| Answer» A. Caustic soda | |
|
Explanation: Sodium hydroxide, also known as lye or caustic soda, has the molecular formula NaOH and is a highly caustic metallic base. It is a white solid available in pellets, flakes, granules, and as a 50% saturated solution. It is used in many industries, mostly as a strong chemical base in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents and as a drain cleaner. |
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| 170. |
Energy stored in a coal is - |
| A. | kinetic energy |
| B. | potential energy |
| C. | chemical energy |
| D. | nuclear energy |
| Answer» C. chemical energy | |
|
Explanation: Chemical energy is stored in coal. Coal is a Hydrocarbon. When coal is burnt its chemical energy comes out in the form of light and heat energy which result in formation of vapors of Carbon Dioxide (CO2) and water(H2O). |
|
| 171. |
Which of the following is the most common element in the Universe? |
| A. | Nitrogen |
| B. | Oxygen |
| C. | Hydrogen |
| D. | Carbon |
| Answer» C. Hydrogen | |
|
Explanation: Hydrogen is the most abundant element in the Universe; helium is second. |
|
| 172. |
wo elements which are used to absorb neutrons to control the chain reaction during nuclear fission are - |
| A. | Boron and Cadmium |
| B. | Boron and Plutonium |
| C. | Cadmium and Uranium |
| D. | Uranium and Boron |
| Answer» A. Boron and Cadmium | |
|
Explanation: Since the continued chain reaction of a nuclear fission reactor depends upon at least one neutron from each fission being absorbed by another fissionable nucleus, the reaction can be controlled by using control rods of material which absorbs neutrons. Cadmium and boron are strong neutron absorbers and are the most common materials used in control rods. In the operation of a nuclear reactor, fuel assemblies are put into place and then the control rods are slowly lifted until a chain reaction can just be sustained. |
|
| 173. |
The most commonly used chemicals in the artificial rainmaking or cloud seeding are |
| A. | Silver Iodide (AgI) |
| B. | Sodium Chloride (NaCl) |
| C. | Dry Ice (Frozen CO2) |
| D. | All of the above |
| Answer» A. Silver Iodide (AgI) | |
|
Explanation: Cloud seeding, a form of intentional weather modification, is the attempt to change the amount or type of precipitation that falls from clouds, by dispersing substances into the air that serve as cloud condensation or ice nuclei, which alter the microphysical processes within the cloud. The usual intent is to increase precipitation (rain or snow), but hail and fog suppression are also widely practiced in airports. The most common chemicals used for cloud seeding include silver iodide and dry ice (solid carbon dioxide). |
|
| 174. |
Which of the following is not a greenhouse gas? |
| A. | Hydrogen |
| B. | Carbon dioxide |
| C. | Nitric oxide |
| D. | Chlorofluorocarbon |
| Answer» A. Hydrogen | |
|
Explanation: A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere. that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone. In the Solar System, the atmospheres of Venus, Mars, and Titan also contain gases that cause greenhouse effects. |
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| 175. |
Wax used for making candle is chemically a mixture of – |
| A. | aliphatic hydrocarbons |
| B. | aromatic hydrocarbons |
| C. | cyclic hydrocarbons |
| D. | aliphatic and aromatic hydrocarbons |
| Answer» A. aliphatic hydrocarbons | |
|
Explanation: An aliphatic compound is a hydrocarbon compound containing carbon and hydrogen joined together in straight chains, branched trains or non-aromatic rings. Waxes are a class of chemical compounds that are plastic (malleable) near ambient temperatures. Characteristically, they melt above 45 degree C (113 degree F) to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, non-polar solvents. All waxes are organic compounds, both synthetic and naturally occurring. Waxes are organic compounds that characteristically consist of long alkyl chains. |
|
| 176. |
The gas used in the artificial ripening of fruits is – |
| A. | Acetylene |
| B. | Methane |
| C. | Ethane |
| D. | Butane |
| Answer» A. Acetylene | |
|
Explanation: Ripening is a process in fruits that causes them to become more palatable. In general, a fruit becomes sweeter, s less green, and softer as it ripens Even though the acidity of fruit increases as it ripens, the higher acidity level does not make the fruit seem tarter, which can lead to the misunderstanding that the riper the fruit the sweeter. Ripening agents speed up the ripening process. They allow many fruits to be picked prior to full ripening, which is useful, since ripened fruits do not ship well. |
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| 177. |
Ruby and sapphire are oxides of – |
| A. | copper |
| B. | tin |
| C. | iron |
| D. | aluminium |
| Answer» D. aluminium | |
|
Explanation: Aluminium forms one stable oxide, known by its mineral name corundum. Sapphire and ruby are impure corundum contaminated with trace amounts of other metals. Corundum is a crystalline form of aluminium oxide (Al2O3) with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally clear transparent materials, but can have differentcolours when impurities are present. Transparent specimens are used as gems, called ruby if red and padparadscha if pink-orange. |
|
| 178. |
Preparation of `Dalda or Vanaspati' ghee from vegetable oil utilizes the following process : |
| A. | Hydrolysis |
| B. | Qxidation |
| C. | Hydrogenation |
| D. | Ozonolysis |
| Answer» C. Hydrogenation | |
|
Explanation: The largest. scale application of hydrogenation is for the processing of vegetable oils (fats to give margarine and related spreads and shortenings). Typical vegetable oils are derived from polyunsaturated fatty acids (containing more than one carbon-carbon double bonds). Their partial hydrogenation reduces most but not all, of these carbon-carbon double bonds. Hydrogenation converts liquid vegetable oils into solid or semi-solid fats, such as those present in margarine. |
|
| 179. |
Smoke is formed due to – |
| A. | Solid dispersed in gas |
| B. | Solid dispersed in liquid |
| C. | gas dispersed in solid |
| D. | gas dispersed in gas |
| Answer» A. Solid dispersed in gas | |
|
Explanation: Smoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires (including stoves, candles, oil lamps, and fireplaces), but may also be used for pest control (cf. fumigation), communication (smoke signals), defensive and offensive capabilities in the military (smoke-screen), cooking (smoked salmon), or smoking (tobacco, cannabis, etc.). |
|
| 180. |
Type metal used in printing press is an alloy of – |
| A. | lead and copper |
| B. | lead and antimony |
| C. | lead and bismuth |
| D. | lead and zinc |
| Answer» B. lead and antimony | |
|
Explanation: In printing, type metal (sometimes called hot metal) refers to the metal alloys used in traditional type founding and hot metal typesetting. Lead is the main constituent of these alloys. Antimony and tin are added to make the character produced durable and tough while reducing the difference between the coefficients of expansion of the matrix and the alloy. Cheap, plentifully available as galena and easily workable, lead has many of the ideal characteristics, but on its own it lacks the necessary hardness and does not make castings with sharp details because molten lead shrinks and sags when it cools to a solid. |
|
| 181. |
Sour taste of 'Coca Cola' is due to the presence of – |
| A. | acetic acid |
| B. | phosphoric acid |
| C. | hydrochloric acid |
| D. | formic acid |
| Answer» B. phosphoric acid | |
|
Explanation: Food-grade phosphoric acid (additive E338) is used to acidify foods and beverages such as various colas, but not without controversy regarding its health effects. It provides a tangy or sour taste and, being a mass- produced chemical, is available cheaply and in large quantities. The low cost and bulk availability is unlike more expensive seasonings that give comparable flavors, such as citric acid which is obtainable from citrus, but usually fermented by Aspergillusniger mold from scrap molasses, waste starch hydrolysates and phosphoric acid. |
|
| 182. |
Which of the following is used in making smoke bombs? |
| A. | Sulphur |
| B. | Phosphorus |
| C. | Hydrogen |
| D. | Carbon |
| Answer» D. Carbon | |
|
Explanation: A smoke bomb is a firework designed to produce smoke upon ignition. Smoke bombs are useful to military units, airsoft games, paintball games, self-defense and pranks. The smoke bomb was first created in 1848, by the inventor Robert Yale. He developed 17th century Chinese-style fireworks and later modified the formula to produce more smoke for a longer period of time. |
|
| 183. |
German silver is an alloy of – |
| A. | copper, nickel and silver |
| B. | silver, copper and aluminium |
| C. | zinc, copper and nickel |
| D. | zinc, silver and copper |
| Answer» C. zinc, copper and nickel | |
|
Explanation: Nickel silver, also known as German silver, Argentan, new silver, nickel brass, albata, alpacca, or electrum, is a copper alloy with nickel and often zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver is named for its silvery appearance, but it contains no elemental silver unless plated. |
|
| 184. |
Acids turn blue litmus into which color? |
| A. | Green |
| B. | Red |
| C. | Pink |
| D. | Colourless |
| Answer» B. Red | |
|
Explanation: Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at 25 °C (77 °F). |
|
| 185. |
Haemoglobin is used to transport in humans. |
| A. | Oxygen |
| B. | Carbon Dioxide |
| C. | Both are correct |
| D. | Both are incorrect |
| Answer» A. Oxygen | |
|
Explanation: In human beings, the respiratory pigment is hemoglobin which has a very high affinity for oxygen. This pigment is present in the red blood corpuscles. |
|
| 186. |
Commercial nitric acid is coloured because it contains dissolved – |
| A. | Oxygen |
| B. | Nitrous oxide |
| C. | Nitrogen dioxide |
| D. | Coloured impurities |
| Answer» C. Nitrogen dioxide | |
|
Explanation: Commercial nitric acid has a brown colour due to dissolved NO2. The procedure of bubbling dry air through warm commercial nitric acid, is to drive away the dissolved nitrogen dioxide so that the acid becomes colourless. |
|
| 187. |
Fertiliser having high nitrogen content is – |
| A. | Urea |
| B. | Ammonium sulphate |
| C. | Ammonium nitrate |
| D. | Calcium citrate |
| Answer» C. Ammonium nitrate | |
|
Explanation: A growth fertilizer will have a high N content and relatively low P and K content. Ammonium nitrate is the highest Nitrogen fertilizer you can buy, and it is potent stuff. It is usually rated as 33-0-0 or 34-0-0. The bag contains 33% or 34% Nitrogen and the other 66% or 67% is inert material. Other formulations of growth fertilizers will contain 5, 6 or even 7 times more Nitrogen than anything else. |
|
| 188. |
Bhopal has tragedy is associated with leakage of – |
| A. | carbon dioxide |
| B. | nitrogen dioxide |
| C. | sulphur dioxide |
| D. | methyl isocyanate |
| Answer» D. methyl isocyanate | |
|
Explanation: The Bhopal disaster, also referred to as the Bhopal has tragedy, was a gas leak incident in India, considered one of the world's worst industrial disasters. It occurred on the night of 2-3 December, 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh. Over 500,000 people were exposed to methyl isocyanate gas and other chemicals. The toxic substance made its way in and around the shantytowns located near the plant. |
|
| 189. |
Bauxite is an alloy of which of the following metals? |
| A. | Aluminium |
| B. | Silver |
| C. | Tin |
| D. | Iron |
| Answer» A. Aluminium | |
|
Explanation: Bauxite is an aluminium ore and is the main source of aluminium. This form of rock consists mostly of the minerals gibbsite Al(OH)3, boehmite, and diaspore, in a mixture with the two iron oxides goethite and hematite, the clay mineral kaolinite, and small amounts of anatase TiO2. |
|
| 190. |
Nucleus of an atom consists of. |
| A. | Proton |
| B. | Neutron |
| C. | Proton and Neutron |
| D. | Electron, Proton and Neutron |
| Answer» C. Proton and Neutron | |
|
Explanation: The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden, under the direction of Rutherford. The proton- neutron model of nucleus was proposed by Dmitry Ivanenko in 1932. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the orbiting electrons. |
|
| 191. |
Where does the oxygen that keeps us alive come from? |
| A. | Carbon dioxide |
| B. | Carbonates absorbed from soil |
| C. | Oxides of minerals |
| D. | Water |
| Answer» D. Water | |
|
Explanation: Since water and carbon dioxide are both compounds which contain oxygen, it is possible to obtain oxygen from either. The oxygen produced from photosynthesis is not released into the air. It is not until cellular respiration that oxygen is released. The oxygen comes from water. The water molecules are split at the "beginning" of photosynthesis for the electrons. These electrons eventually make their way to the electron transport chain, where oxygen is the final electron accept, and then released into the air. Scientists agree that there's oxygen from ocean plants in every breath we take. |
|
| 192. |
The gas used for artificial fruit ripening of green fruit is – |
| A. | Ethylent |
| B. | Acetylene |
| C. | Ethane |
| D. | Methane |
| Answer» A. Ethylent | |
|
Explanation: Ethylene can promote ripening in tomatoes, bananas, citrus, pineapples, dates, persimmons, pears, apples, melons, mangos, avocados, papayas and jujubes - a clear indication that the action of ethylene is general and widespread amongst a number of fruits. It is clear that ethylene is a ripening hormone - achemical substance produced by fruits with the specific biological phenomenon of accelerating the normal process of fruit maturation and senescence. |
|
| 193. |
Magnets attract magnetic substances are iron, nickel, cobalt, etc. They can also repel - |
| A. | paramagnetic substances |
| B. | ferromagnetic substances |
| C. | diamagnetic substances |
| D. | non-magnetic substances |
| Answer» C. diamagnetic substances | |
|
Explanation: Those materials which when placed in a magnetic field become weakly magnetized in a direction opposite to that of the applied field, are called as diamagnetic materials. Example: bismuth, antimony, copper, gold, quartz, mercury, water, alcohol, air, hydrogen etc. |
|
| 194. |
Atomic mass of Sulphur is 32u. The number of moles in 16 games of Sulphur is: |
| A. | 1 mole of Sulphur |
| B. | 0.5 moles of Sulphur |
| C. | 0.75 moles of Sulphur |
| D. | 0.25 moles of Sulphur |
| Answer» B. 0.5 moles of Sulphur | |
|
Explanation: The molar mass of a com pound is equal to the sum of the atomic masses of its con stituent atoms in g/mol. |
|
| 195. |
A metal is exposed to the atmosphere for some time. It becomes coated with green carbonate. The metal must be – |
| A. | silver |
| B. | copper |
| C. | aluminium |
| D. | zinc |
| Answer» B. copper | |
|
Explanation: Copper forms a rich variety of compounds with oxidation states +1 and +2, which are often called cuprous and cupric, respectively. It does not react with water, but it slowly reacts with atmospheric oxygen forming a layer of brown-black copper oxide. In contrastto the oxidation of iron by wet air, this oxide layer stops the further, bulk corrosion. |
|
| 196. |
Whic of the following pairs of materials serves as electrodes in chargeable batteries commonly used in devices such as torch lights, electric shavers, etc.? |
| A. | Iron and cadmium |
| B. | Nickel and cadmium |
| C. | Lead peroxide and lead |
| D. | Zinc and carbon |
| Answer» B. Nickel and cadmium | |
|
Explanation: A rechargeable battery, storage battery, or accumulator is a type of electrical battery. It comprises one or more electrochemical cells, and is a type of energy accumulator. It is known as a secondary cell because its electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging from button cells to megawatt systems connected to stabilize an electrical distribution network. |
|
| 197. |
Iodized salt is beneficial for – |
| A. | lowering of blood pressure |
| B. | prevention of dehydration |
| C. | thyroid function |
| D. | salivary glands |
| Answer» C. thyroid function | |
|
Explanation: Iodized salt (also spelled iodised salt) is table salt mixed with a minute amount of various salts of the element iodine. The ingestion of iodide prevents iodine deficiency. Worldwide, iodine deficiency affects about two billion people and is the leading preventable cause of mental retardation. Deficiency also causes thyroid gland problems, including "endemic goitre." In many countries iodine deficiency is a major public health problem that can be cheaply addressed by purposely adding small amounts of iodine to the sodium chloride salt. |
|
| 198. |
Which of the following chemicals is used in photography? |
| A. | Aluminium hydroxide |
| B. | Silver bromide |
| C. | Potassium nitrate |
| D. | Sodium chloride |
| Answer» B. Silver bromide | |
|
Explanation: Silver bromide (AOBr), a soil , pale-yellow, water insoluble salt well known (along with other silver hali(les) for its unusual sensitivity to light:. This properly has allowed silver halides to become the basis of modern photographic materials. AgBr is widely used in photographic films and is believed by some to have been used for making the Shroud of Turin. The salt can be found naturally as the mineral bromargyrite (bromyrite). |
|
| 199. |
Fungi are plants that lack - |
| A. | Oxygen |
| B. | Carbon dioxide |
| C. | Chlorophyll |
| D. | None of these |
| Answer» C. Chlorophyll | |
|
Explanation: We know plants prepare their own food and so are known as autotrophs. With the help of photosynthesis they make food in which they produce glucose from carbon dioxide and sunlight. |
|
| 200. |
The gas which turns into liquid at the lowest temperature among the following is – |
| A. | hydrogen |
| B. | oxygen |
| C. | helium |
| D. | nitrogen |
| Answer» A. hydrogen | |
|
Explanation: Liquid hydrogen (LH2) is the liquid state, of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below hydrogen's critical point of 33 K. However, for hydrogen to be in a full liquid state without evaporating at atmospheric pressure, it needs to be cooled to 20.28 K (-423.17 °F/-252.87°C). One common method of obtaining liquid hydrogen involves a compressor resembling a jet engine in both appearance and principle. |
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