1240+ Chemistry Solved MCQs


Tar roads get damaged if there is –

A. stagnation of water on road
B. heavy traffic
C. no maintenance
D. no sloping
Answer» A. stagnation of water on road
Explanation: 0

The drug 'Marijuana' is a –

A. sedative
B. mental stimulant
C. hallucinating substance
D. tranquillizer
Answer» A. sedative
Explanation: Cannabis, also known as marijuana is a preparation of the Cannabis plant intended for use as a psychoactive drug and as medicine. Cannabis indica is known for sedative effects and preferred night time as medical cannabis.

Chemically 'Quick Silver’ is known as

A. Mercury
B. Silver
C. Gold
D. Copper
Answer» A. Mercury
Explanation: Quicksilver is an alternative name for the element mercury. A heavy, silvery d- block element, mercury is the only metal that is liquid at standard conditions for temperature and pressure; the only other element that is liquid under these conditions is bromine, though metals such as caesium, gallium, and rubidium melt just above room temperature.

Extensively used nitrogenous fertilizer is –

A. Ammonium nitrate
B. Urea
C. Ammonium sulphate
D. Nitro-lime
Answer» B. Urea
Explanation: More than 90% of world production of urea is destined for use as a nitrogen-release fertilizer. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use. Therefore, it has the lowest transportation costs per unit of nitrogen nutrient.

The metal used in storage batteries-

A. Iron
B. Copper
C. Lead
D. Zinc
Answer» C. Lead
Explanation: Commercially available batteries use a variety of metals and electrolytes. Anodes can be made of zinc, aluminum, lithium, cadmium, iron, metallic lead, lanthanide, or graphite

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: Lead and antimony are used to make type metals alloy. These type metals are used to make the character produced durable and tough.

The acid which is secreted by the glands in the stomach wall is –

A. sulphuric acid
B. hydrochloric acid
C. nitric acid
D. phosphoric acid
Answer» B. hydrochloric acid
Explanation: Gastric acid is a digestive fluid, formed in the stomach. It has a pH of 1.5 to 3.5 and is composed of hydrochloric acid (HCl) (around 0.5%, or 5000 parts per million), and large quantities of potassium chloride (KCl) and sodium chloride (NaCl). The acid plays a key role in digestion of proteins, by activating digestive enzymes, and making ingested proteins unravel so that digestive enzymes can break down the long chains of amino acids.

Dry ice is –

A. solid ammonia
B. solid sulphur dioxide
C. dry carbon dioxide gas
D. solid carbon dioxide
Answer» D. solid carbon dioxide
Explanation: Dry ice is the solid form of carbon dioxide. It is used primarily as a cooling agent. Its advantages include lower temperature than that of water ice and not leaving any residue. It is useful for preserving frozen foods, ice cream, etc., where mechanical cooling is unavailable.

Cement containing excess amount of lime –

A. cracks during setting
B. becomes more strong
C. is slow setting
D. is quick setting
Answer» A. cracks during setting
Explanation: In cement almost entire amount of lime is present in combined state as calcium silicates and calcium aluminates. Cement containing excess amount of lime cracks during setting while cement containing less amount of lime is weak in strength. Setting of cement is an exothermic process.

Which one of the following is a micro- element?

A. Chlorine
B. Hydrogen
C. Nitrogen
D. Oxygen
Answer» A. Chlorine
Explanation: In analytical chemistry, a trace element or micro-element is an element in a sample that has an average concentration of less than 100 parts per million measured in atomic count or less than 100 micrograms per gram. These are those elements essential for plant growth which are needed in only very small (micro). They are: boron (B), copper (Cu), iron (Fe), chloride (C1), manganese (Mn), molybdenum (Mo) and zinc (Zn).

In vulcanization, natural rubber is heated with-

A. Carbon
B. Sulphur
C. Silicon
D. Phosphorus
Answer» B. Sulphur
Explanation: Vulcanization of rubber is a process of improvement of the rubber elasticity and strength by heating it in the presence of sulfur, which results in three-dimensional cross- linking of the chain rubber molecules(polyisoprene) bonded to each other by sulfur atoms.

An example of major air pollutant is –

A. Oxygen
B. Carbon monoxide
C. Helium
D. Carbon dioxide
Answer» B. Carbon monoxide
Explanation: Carbon monoxide (CO) is a colourless, odorless, non-irritating but very poisonous gas which is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.

The metal, used to galvanise iron to protect it from rusting is -

A. Zine
B. Chromium
C. Lead
D. Antimony
Answer» A. Zine
Explanation: Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting. Although galvanization can be done with electrochemical and electro-deposition processes, the most common method in current use is hot-dip galvanization, in which steel parts are submerged in a bath of molten zinc.

Which of the following gases is mixed with oxygen for breathing by divers in aqualungs?

A. Methane
B. Nitrogen
C. Helium
D. Hydrogen
Answer» B. Nitrogen
Explanation: For some diving, has mixtures other than normal atmospheric air (21 % oxygen, 78% nitrogen, 1% trace gases) can be used, so long as the diver is properly trained in their use. The most commonly used mixture is Nitrox, also referred to as Enriched Air Nitrox (EAN), whichis air with extra oxygen, often with 32% or 36% oxygen, and thus less nitrogen, reducing the likelihood of decompression sickness or allowing longer exposure to the same pressure for equal risk.

The material known in commerce as Terylene is a –

A. Synthetic fibre
B. Natural fibre
C. Modified natural fibre
D. Blend of cotton and silk
Answer» A. Synthetic fibre
Explanation: Terylene is the name for a synthetic polyester fibre. It is a synthetic polyester fibre or fabric based on terephthalic acid, characterized by lightness and crease resistance and used for clothing, sheets, ropes, sails, etc.

Among the fuels given below, the one with highest calorific value is –

A. Coke
B. Coal
C. Wood
D. Natural gas
Answer» D. Natural gas
Explanation: The calorific values of different fuels (in Kcal/kg) in dry state are: Wood: 3500; Coal: 4000-7000; Coke: 6500; and Natural Gas: 8600 Kcal/kg.

Electric bulbs are filled with –

A. Nitrogen
B. Carbon dioxide
C. Argon
D. Oxygen
Answer» C. Argon
Explanation: Argon is produced industrially by the fractional distillation of liquid air. Argon is mostly used as an inert shielding has in welding and other high-temperature industrial processes where ordinarily non-reactive substances become reactive; for example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning. Argon basalso has uses in incandescent and fluorescent lighting, and other types of gas discharge tubes. Argon makes a distinctive blue-green gas laser.

The purest form of Iron is :

A. Cast iron
B. Steel
C. Pig iron
D. Wrought iron
Answer» D. Wrought iron
Explanation: Wrought iron is an iron alloy with a very low carbon content in Contrast to steel, and has fibrous inclusions, known as slag. This is what gives it a "grain" resembling wood, which is visible when it is etched or bent to the point of failure. Wrought iron is tough, malleable, ductile and easily welded. Historically, it was known as "commercially pure iron"; however, it no longer qualifies because current standards for commercially pure iron require a carbon content of less than 0.008 wt%.

Which of the following metals are present in hemoglobin and chlorophyll, respectively?

A. Fe and Mg
B. Fe and Zn
C. Mg and Zn
D. Zn and Mg
Answer» A. Fe and Mg
Explanation: Fe and Mg metals are present in hemoglobin and Chlorophyll respectively.

Atomic mass of Nitrogen is 14 and that of Hydrogen is 1. What will be the molecular mass of Ammonia?

A. 18
B. 17
C. 16
D. 15
Answer» B. 17
Explanation: Ammonia (NH3) is composed of one atom of Nitrogen and three Hydrogen atoms. This means that its molar mass of ammonia will be the sum of the molar mass of one nitrogen atom and three times the molar mass of a hydrogen atom.

Silver halides are used in photographic plates because they are -

A. oxidised in air
B. soluble in hyposolution
C. reduced by light
D. totally colourless
Answer» C. reduced by light
Explanation: The light-sensitive chemicals used in photographic film and paper are silver halides. Silver halides are used in photographic film and photographic paper, including graphic art film and paper, where silver halide crystals in gelatin are coated on to a film base, glass or paper substrate. When a silver halide crystal is exposed to light, a sensitivity speck on the surface of the crystal is turned into a small speck of metallic silver (these comprise the invisible or latent image). If the speck of silver contains approximately four or more atoms, it is rendered developable - meaning that it can undergo development which turns the entire crystal into metallic silver.

Tetra ethyle lead (TEL) is -

A. a catalyst in burning fossil fuel
B. an antioxidant
C. areductant
D. an antiknock compound
Answer» D. an antiknock compound
Explanation: Tetraethyl lead was extensively used as an additive to gasoline, wherein it served as an effective antiknock agent and prevented exhaust valve and seat wear. The use of TEL in gasoline started in the US, while in Europe, alcohol was initially used. The advantages of leaded gasoline — its higher enemy content and storage quality —eventually led to a universal switch to leaded fuel. One of the greatest advantages of TEL over other antiknock agents or the use of high-octane blend stocks is the very

Which metal is heaviest -

A. osmium
B. mercury
C. iron
D. nickel
Answer» A. osmium
Explanation: I assume by "heaviest," you mean "densest;" in that case, the densest chemical element is osmium (which is a metal). Osmium has a density of around 22 grams per cubic centimeter.

The term PVC used in the plastic industry stands for -

A. polyvinyl chloride
B. polyvinyl carbonate
C. phosphor vanadium chloride
D. phosphavinyl chloride
Answer» A. polyvinyl chloride
Explanation: Polyvinyl chloride is the world's third-most widely produced synthetic plastic polymer, after polyethylene and polypropylene. About 40 million tones are produced per year.

Rusting of iron takes place due to –

A. oxidation
B. carbonation
C. exfoliation
D. corrosion
Answer» A. oxidation
Explanation: The rusting of iron is an electrochemical process that begins with the transfer of electrons from iron to oxygen. The rate of corrosion is affected by water and accelerated by electrolytes, as illustrated by the effects of road salt on the corrosion of automobiles. When impure (cast) iron is in contact with water, oxygen, or other strong oxidants, or acids, it rusts.

German silver used for making utensils is an alloy of –

A. Copper, silver, nickel
B. Copper, zinc, nickel
C. copper, zinc, aluminium
D. copper, nickel, aluminium
Answer» B. Copper, zinc, 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. The name "German silver" refers to its development by 19th-century German metalworkers in imitation of the Chinese alloy known as paktong.

Sour milk contains –

A. acetic acid
B. tartaric acid
C. citric acid
D. lactic acid
Answer» D. lactic acid
Explanation: Lactic acid, also known as milk acid, is a chemical compound that plays a role in various biochemical processes and was first isolated in 1780 by the Swedish chemist Carl Wilhelm Scheele. Lactic acid is a carboxylic acid with the chemical formula C3H6O3. Lactic acid is found primarily in sour milk products, such as koumiss, laban, yogurt, kefir, and some cottage cheeses. The casein in fermented milk is coagulated (curdled) by lactic acid.

The acid used in lead storage cells is –

A. phosphoric acid
B. hydrochloric acid
C. nitric acid
D. sulphuric acid
Answer» D. sulphuric acid
Explanation: Lead-acid batteries, invented in 1859 by French physicist Gaston Plante, are the oldest type of rechargeable battery. Despite having a very low energy-to-weight ratio and a low energy-to-volume ratio, their ability to supply high surge currents means that the cells maintain a relatively large powerto-weight ratio.These features, along with their low cost, make them attractive for use in motor vehicles to provide the high current required by automobile starter motors.

Milk is an example of -

A. suspension
B. true solution
C. emulsion
D. gel
Answer» C. emulsion
Explanation: Milk is an example of the oil-in- water type of emulsion. In milk liquid fat globules are dispersed in water. Other examples are, vanishing cream etc.

Wood Spirit is which of the following?

A. Ethyl Alcohol
B. Propanol
C. Methyl Alcohol
D. Butanol
Answer» C. Methyl Alcohol
Explanation: Wood spirit (countable and uncountable, plural wood spirits) (countable) A dryad or other spiritual being associated with forests, woods, or trees. (Uncountable, often the wood spirit) Methyl Alcohol, a type of alcohol.

Alum stops bleeding in minor cuts because of –

A. solvation
B. emulsion
C. dialysis
D. coagulation
Answer» D. coagulation
Explanation: Coagulation is the process by which blood forms clots. It is an important part of homeostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin- containing clot to stop bleeding and begin repair of the damaged vessel. Disorders of coagulation can lead to an increased risk of bleeding (hemorrhage) or obstructive clotting (thrombosis).

'Plaster of Paris' is made by partial dehydration of –

A. epsom salt
B. gypsum salt
C. blue vitriol
D. green vitriol
Answer» B. gypsum salt
Explanation: Plaster is a building material used for coating walls and ceilings. Plaster starts as a dry powder similar to mortar or cement and like those materials it is mixed with water to form apaste which liberates heat and then hardens. Unlike mortar and cement, plaster remains quite soft after setting, and can be easily manipulated with metal tools or even sandpaper. These characteristics make plaster suitable for a finishing, rather than a load-bearing material.

The purity of gold is expressed in carats. The purest form of gold is–

A. 24 carats
B. 99.6 carats
C. 91.6 carats
D. 22 carats
Answer» A. 24 carats
Explanation: Gold is a dense, soft, shiny, malleable and ductile metal. Gold has a bright yellow colour and luster traditionally considered attractive, which it maintains without oxidizing in air or water. The metal therefore occurs often in free elemental (native) form, as nuggets or grains in rocks, in veins and in alluvial deposits. Less commonly, it occurs in minerals as gold compounds, usually with tellurium. Pure gold is too soft for day-to-day monetary use and is typically hardened by alloying with copper, silver or other base metals. The gold content of alloys is measured in carats (k). Pure gold is designated as 24k.

Petroleum consists of a mixture of –

A. Carbohydrates
B. Carbonates
C. Hydrocarbons
D. Carbides
Answer» C. Hydrocarbons
Explanation: Petroleum (petroleum, from Latin: 'petra' (rock) + Latin: oleum (oil) or crude oil is a naturally occurring flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compoun.ds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling. It is refined and separated, most easily by boiling point, into a large number of consumer products, from petrol (or gasoline) and kerosene to asphalt and chemical reagents used to make plastics and pharmaceuticals. Petroleumis used in manufacturing a wide variety of materials, and it is estimated that the world consumes about 88 million barrels each day.

What is a mixture of potassium nitrate powdered charcoal and sulfur called?

A. paint
B. aluminum
C. brass
D. gun powder
Answer» D. gun powder
Explanation: Gun powder is the mixture of potassium nitrate powdered charcoal and sulfur.

What among following is used to produce artificial rain?

A. Copper oxide
B. carbon monoxide
C. silver iodide
D. silver nitrate
Answer» C. silver iodide
Explanation: Artificial process of making rain is done by precipitation, a process of condensation of water vapors in the air. This is done by using cloud seeding chemicals like potassium iodide, silver iodide, liquid propane or solid carbon dioxide (dry ice).

The isotope used for the production of atomic energy is -

A. U-235
B. U-238
C. U-234
D. U-236
Answer» A. U-235
Explanation: U235 is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope U238 it is fissile, i.e., it can sustain fission chain reaction. It is the only fissile isotope that is a primordial nuclide or found in significant quantity in nature. If at least one neutron from U235 fission strikes another nucleus and causes it to fission, then the chain reaction will continue. If the reaction will sustpa itself, it is said to be critical, and the massof U required to produce the critical condition is said to be a critical mass.

Which of the following is not a nucleon?

A. Proton
B. Neutron
C. Electron
D. Positron
Answer» D. Positron
Explanation: Nucleon is one of the particles that makes up the atomic nucleus. Each atomic nucleus consists of one or more nucleons, and each atom in turn consists of a cluster of nucleons surrounded by one or more electrons. There are two kinds of nucleon: the neutron and the proton. The mass number of a given atomic isotope is identical to its number of nucleons. Thus the term nucleon number may be used in place of the more common terms mass number or atomic mass number.

Which of the metallic ions is essential for blood clotting?

A. Na+
B. Ca++
C. K+
D. Fe++
Answer» B. Ca++
Explanation: Clotting also requires: calcium ions (Ca2+)(which is why blood banks use a chelating agent to bind the calcium in donated blood so the blood will not clot in the bag). about a dozen other protein clotting factors.

CuO + H2 = Cu + H2O. This equation is an example of -

A. Oxidation
B. Decomposition
C. Reduction
D. Redox
Answer» D. Redox
Explanation: 0

The gas that is used in the manufacture of vanaspati ghee is -

A. Oxygen
B. Carbon dioxide
C. Hydrogen
D. Nitrogen
Answer» C. Hydrogen
Explanation: Hydrogenation - to treat with hydrogen - is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. The largest scale application of hydrogenation is for the processing of vegetableoils (fats to give margarine and related spreads and shortenings).

The anode of a dry cell is made up of -

A. Iron
B. Cadmium
C. Zine
D. Lead
Answer» C. Zine
Explanation: A standard dry cell comprises a zinc anode (negative pole), usually in the form of a cylindrical pot, with a carbon cathode (positive Pole) in the form of a central rod. The electrolyte is ammonium chloride in the form of a paste next to file zinc anode. The remaining space between the electrolyte and carbon etthode is taken up bye. second paste consisting of amoniumm chloride and manganese dioxide, the latter acting as a depolariser.

The chemical used in enabalining biological materials is –

A. formaldehyde in water
B. formaldehyde in methanol
C. ethylene glycol
D. gaseous formaldehyde
Answer» A. formaldehyde in water
Explanation: Embalming fluids use formaldehyde as a preservative. Formaldehyde is the simplest aldehyde with the chemical formula HCHO. Formalin is a solution offormaldehyde in water, usually with a small amount of methanol added. Modern formaldehyde based embalming fluids are much kinder to the environment than those used in previous years.

Which of the following is a mono- atomic gas?

A. Oxygen
B. Neon
C. Nitrogen
D. Fluorine
Answer» B. Neon
Explanation: All elements will be monatomic in the gas phase at sufficiently high temperatures. At standard temperature and pressure (STP), all of the noble gases are monatomic. These are helium, neon, argon, krypton, xenon and radon. Monatomic hydrogen comprises about 75% of the elemental mass of the universe.

Among the following, which is always found in free-state in nature?

A. Gold
B. Silver
C. Sodium
D. Copper
Answer» A. Gold
Explanation: 0

In a nuclear reactor the material use for absorbing neutrons is –

A. zinc
B. radium
C. lead
D. cadmium
Answer» D. cadmium
Explanation: One isotope of cadmium, 113Cd, absorbs neutrons with very high probability if they have an energy below the cadmium cut-off and transmits them otherwise. The cadmium cut- off is about 0.5 eV. Neutrons with energy below the cut-off are deemed slow neutrons, distinguishing them from intermediate and fast neutrons.

Solder metal is an alloy of –

A. lead and tin
B. lead and antimony
C. copper and zinc
D. copper and tin
Answer» A. lead and tin
Explanation: A solder is a fusible metal alloy of tin and lead with a melting point or melting range of 90 to 450°C, used in a process called soldering where it is melted to jain metallic surfaces. It is especially useful in electronics and plumbing.

Ozone depletion in the atmosphere is mainly caused by -

A. sulphur dioxide
B. nitrogen dioxide
C. hydrogen sulphide
D. chlorofluorocarbon
Answer» D. chlorofluorocarbon
Explanation: A chlorofluorocarbon (CFC) is an organic compound that contains only carbon, chlorine, hydrogen and fluorine, produced as a volatile derivative of methane and ethane. They contribute to ozone depletion in the upper atmosphere.

All noble gases are -

A. Colourless
B. Odourless
C. Colourless and Odourless
D. Light blue
Answer» C. Colourless and Odourless
Explanation: Other characteristics of the noble gases are that they all conduct electricity, fluoresce, are odorless and colorless, and are used in many conditions when a stable element is needed to maintain a safe and constant environment.

Which halide is used in making sensitive emulsion on photographic film?

A. Sodium chloride
B. Silver bromide
C. Silver iodide
D. Silver chloride
Answer» B. Silver bromide
Explanation: Silver bromide, a soft, pale- yellow, water insoluble salt well known for its unusual sensitivity to light. This property has allowed silver halides to become the basis of modern photographic materials.

Among the following the hardest metal is –

A. Gold
B. Iron
C. Platinum
D. Tungsten
Answer» D. Tungsten
Explanation: Titanium is the hardest natural metal in the world. It is very strong, three times the strength of steel and much stronger than gold, silver and platinum and yet is very light weight. Tungsten carbide is the hardest metal alloy on Earth and is scratch proof under normal wear. Tungsten carbide is two times as hard as steel and four times as hard as titanium.

Hardest allotrope of carbon is -

A. diamond
B. graphite
C. coke
D. lamp black
Answer» A. diamond
Explanation: Diamond is one well known allotrope of carbon. The hardness and high dispersion of light of diamond make it useful for both industrial applications and jewellery. Diamond is the hardest known natural mineral. This makes it an excellent abrasive and makes it hold polish and luster extremely well.

The depletion of ozone layer is due to -

A. chloro fluoro carbon
B. carbon dioxide
C. sulphur dioxide
D. ethane
Answer» A. chloro fluoro carbon
Explanation: A chlorofluorocarbon (CFC) is an organic compound that contains only carbon, chlorine, hydrogen and fluorine, produced as a volatile derivative of methane and ethane. The manufacture of such compounds has been phased out (and replaced with products such as R-4104 by the Montreal Protocol because they contribute to ozone depletion in the upper atmosphere.

Sodium bicarbonate is commercially known as –

A. Washing soda
B. Baking soda
C. Caustic soda
D. Soda lime
Answer» B. Baking soda
Explanation: Baking Soda is Sodium bicarbonate or sodium hydrogen carbonate. It is primarily used in cooking (baking), as a leavening agent. It reacts with acidic components in batters, releasing carbon dioxide, which causes expansion of the batter and forms the characteristic texture and grain in pancakes, cakes, quick breads, soda bread, and other baked and fried foods.

Coal is formed from –

A. crude oil
B. deposit of animal waste
C. coke
D. compressed and hardened biomass
Answer» D. compressed and hardened biomass
Explanation: A fossil fuel, coal forms when dead plant matter is converted into peat, which in turn is converted into lignite, then sub- bituminous coal, after that bituminous coal, and lastly anthracite: This involves biological and geological processes that take place over a long period.

An example of semiconductor is -

A. German silver
B. Germanium
C. Phosphorous
D. Arsenic
Answer» B. Germanium
Explanation: Purified germanium is a semiconductor, with appearance most similar to elemental silicon. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature. Unlike silicon, it is too reactive to be found naturally on Earth in the free (native) state.

Non-stick kitchenwares are coated with

B. Graphite
C. Teflon
D. Silicon
Answer» C. Teflon
Explanation: Polytetrafluoroethylene (FYIFE) is a synthetic fluoropolymer of tetrafluoroethylene that finds numerous applications. The best known brand name of FIFE is Teflon. PTFE is used as a non-stick coating for pans and other cookware as it is hydrophobic and possesses fairly high heat resistance.

‘Freon' used as refrigerants is chemically known as -

A. chlorinated hydrocarbon
B. fluorinated hydrocarbon
C. chlorofluoro hydrocarbon
D. fluorinated aromatic compound
Answer» C. chlorofluoro hydrocarbon
Explanation: In addition to fluorine and carbon, Freons often contain hydrogen, chlorine, or bromine. Thus, Freons are types of chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and related compounds.

The material used in the manufacture of lead pencil is –

A. Graphite
B. Lead
C. Carbon
D. Mica
Answer» A. Graphite
Explanation: Pencils create marks via physical abrasion, leaving behind a trail of solid core material that adheres to a sheet of paper or other surface. They are noticeably distinct from pens, which dispense liquid or gel ink that stain the light colour of the paper. Most pencil cores are made of graphite mixed with a clay binder, leaving grey or black marks that can be easily erased.

If all bullets could not be removed from gun shot injury of a man, it may cause poisoning by –

A. Mercury
B. Lead
C. Iron
D. Arsenic
Answer» B. Lead
Explanation: Lead is used in building construction, lead-acid batteries, bullets and shot, weights, as part of solders, pewters, fusible alloys, and as a radiation shield. Lead has the highest atomic number of all of the stable elements, although the next higher element, bismuth, has a half-life that is so long (much longer than the age of the universe) that it can be considered stable. Its four stable isotopes have 82 protons, a magic number in the nuclear shell model of atomic nuclei.

Nail polish remover contains?

A. Benzene
B. acetic acid
C. acetone
D. petroleum ether
Answer» C. acetone
Explanation: Acetone can remove artificial nails made of acrylic or cured gel. A less harsh nail polish remover is ethyl acetate, which often also contains isopropyl alcohol. Ethyl acetate is usually the original solvent for nail polish itself.

Which of the following metals is NOT obtained by reduction using carbon?

A. Copper
B. Sodium
C. Iron
D. Zinc
Answer» B. Sodium
Explanation: Metals such as zinc, iron and copper are present in ores as their oxides. Each of these oxides is heated with carbon to obtain the metal.

One of the following is used to dissolve noble metals. That is –

A. Nitric acid
B. Hydrochloric acid
C. Sulphuric acid
D. Aqua ragia
Answer» D. Aqua ragia
Explanation: Aqua regia ("royal water"), aqua aegis ("king's water"), or nitro-hydrochloric acid is a highly corrosive mixture of acids, a fuming yellow or red solution. The mixture is formed by freshly mixing concentrated nitric acid and hydrochloric acid, usually in a volume ratio of 1:3. It was named so because it can dissolve the so-called royal or noble metals, gold and platinum. However, titanium, iridium, ruthenium, tantalum, osmium, rhodium and a few other metals are capable of withstanding its corrosive properties.

Water can be separated from alcohol water mixture by –

A. decantation
B. evaporation
C. distillation
D. sublimation
Answer» C. distillation
Explanation: Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction. Commercially, distillation has a number of applications. It is used to separate crude oil into more fractions for specific uses such as transport, power generation and heating. Water is distilled to remove impurities, such as salt from seawater. Air is distilled to separate its components— notably oxygen, nitrogen, and argon— for industrial use.

'Milk Sugar' is –

A. Lactose
B. Maltose
C. Galactose
D. Sucrose
Answer» A. Lactose
Explanation: Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2-8% of milk (by weight), although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from lac or lactis, the Latin word for milk, plus the -ose ending used to name sugars. It has a formula of C12H22O11. Food industry applications, both of pure lactose and lactose- containing dairy by-products, have markedly increased since the 1960s.

Which of the following is not a nitrogenous fertilizer?

A. Ammonium sulphate
B. Urea
C. Ammonium nitrate
D. Superphosphate
Answer» D. Superphosphate
Explanation: Superphosphate is a common synthetic phosphorus fertilizer.

Which of the following is chief source of Naphthalene?

A. Moth balls
B. Moth flakes
C. Tar Camphor
D. Methyl Alcohol
Answer» C. Tar Camphor
Explanation: Petroleum-derived naphthalene is usually purer than that derived from coal tar.

Which of the following is the petroleum wax?

A. Bees wax
B. Carnauba wax
C. Paraffin wax
D. Jojoba wax
Answer» C. Paraffin wax
Explanation: Waxes are a class of chemical compounds that are plastic (malleable) near ambient temperatures. Characteristically, they melt above 45 °C, (113 °F) to give a lowviscosity liquid. Waxes are insoluble in water but soluble in organic, non-polar solvents. All waxes are organic compounds, both synthetic and naturally occurring.

Which variety of coal contains recognizable traces of the original plant material?

A. Anthracite
B. Lignite
C. Peat
D. Bitumen
Answer» C. Peat
Explanation: Peat contains recognizable traces of the original plant material. Initially the peat is converted into lignite or 'brown coal' - these are coal-types with low organic maturity. In comparison to other coals, lignite is quite soft and its colour can range from dark black to various shades of brown.

Sodium calcium silicate is called.

A. Hard glass
B. Borosilicate glass
C. Soft glass
D. Jena glass
Answer» C. Soft glass
Explanation: Ordinary glass which is also known as soda glass or soft glass is a mixture of sodium silicate, Calcium silicate, and Silica.

A gas used as a disinfectant in drinking water is -

A. Hydrogen
B. Oxygen
C. Fluorine
D. Chlorine
Answer» D. Chlorine
Explanation: Water chlorination is the process of adding chlorine or chlorine compounds such as sodium hypochlorite to water.

Who developed atom bomb?

A. Warn& Wan Brown
B. J. Robert Openheimer
C. Edward Taylor
D. Samuel Koehen
Answer» B. J. Robert Openheimer
Explanation: J. (Julius) Robert Oppenheimer was born in New York City on April 22, 1904. Under Oppenheimer's guidance, the laboratories at Los Alamos were constructed. There, he brought the best minds in physics to work on the problem of creating an atomic bomb. In the end, he was managing; more than 3,000 people, as well as tackling theoretical and mechanical problems that arose. He is often referred to as the "father" of the atomic bomb.

The major harmful gas emitted by automobile vehicle which causes air pollution is –

A. Carbon Monoxide
B. Methane
C. Carbon dioxide
D. Ozone gas
Answer» A. Carbon Monoxide
Explanation: Carbon monoxide is the major harmful gas emitted by the automobile vehicles which causes air pollution. Carbon monoxide (CO) - A product of incomplete combustion, carbon monoxide reduces the blood’s ability to carry oxygen; overexposure (carbon monoxide poisoning) may be fatal. Carbon Monoxide poisoning is a major killer.

Humburger effect is otherwise known as-

A. Sodium pump
B. Anaerobic metabolism
C. Choloride shift
D. Respiratory product
Answer» C. Choloride shift
Explanation: Hamburger shift (also known as the Chloride shift) is a process which occurs in the cardiovascular system and refers to the exchange of bicarbonate and chloride across the membrane of red blood cells

The purest form of water in nature is –

A. Rain water
B. Lake water
C. River water
D. Sea water
Answer» A. Rain water
Explanation: Rainwater is often considered the purest form of water available on the Earth. The evaporation of water by the sun allows the salts and other impurities to be left behind out of the water. However, in reality, rain water is often much less than pure when it reaches the surface of the Earth due to the high pollution of air with toxic gases.

The element used for making solar cells is -

A. Magnesium
B. Sodium
C. Calcium
D. Silicon
Answer» D. Silicon
Explanation: Materials presently used for photovoltaic solar cells include mono-crystalline silicon, polycrystaijhne silicon, amorphous silicon, cadmium telluride, and copper indium selenideisulfide.

What is the number of atoms constituting a molecule known as -

A. Atomic number
B. Isotopes
C. Atomic mass
D. Atomicity
Answer» D. Atomicity
Explanation: Atomicity is the total number of atoms present in one molecule of an element.

If water smells bad, then that odour can be removed by adding -

A. alum
B. bleach
C. activated carbon
D. deactivated nitrogen
Answer» C. activated carbon
Explanation: Adding powdered activated carbon to water or using of granular activated carbon (GAC) in the water filter can remove bad taste and foulodor.

Substance used as an anti-freeze in radiators of automobiles is :

A. Methyl alcohol and H2O
B. Methy] alcohol
C. Ethyl alcohol
D. Ethyl alcohol and H2O
Answer» A. Methyl alcohol and H2O
Explanation: Methyl alcohol and water are used as an anti-freeze in radiators of automobiles.

The function of sedimentation tank in sewage treatment is to:

A. Disinfect the sewage
B. Remove water content
C. Aerate the sewage
D. Remove suspended solids
Answer» D. Remove suspended solids
Explanation: The function of sedimentation tank in the sewage treatment is to remove suspended solids.

Wich of the following is a method/process of disposing of solid waste which cannot be re-used or recycled?

A. Landfills
B. Incineration
C. Pyrolysis and Gasification
D. An the above
Answer» D. An the above
Explanation: Landfills, Incineration, Pyrolysis and Gasification are methods of disposing of solid waste which cannot be reused or recycled.

The weight of 6.023 x 1022 atoms of carbon is –

A. 12 gms
B. 120 gms
C. 1.2 gms
D. 0.12 gms
Answer» A. 12 gms
Explanation: The number is known as Avogadro 's Number which is the number of atoms in 12g of the isotope carbon-12. carbon atoms weigh = 12 grams.

Sulphur dioxide bleaches colouring matter by –

A. Reduction
B. Dehydration
C. Decomposition
D. Oxidation
Answer» A. Reduction
Explanation: Sulphur dioxide gas exhibits bleaching properties in presence of moisture. It dissolves in water liberating nascent hydrogen. Nascent hydrogen removes oxygen atoms from the colouring matter (reduces colouring matter) and it loses its colour.

Which of the following elements is not radioactive?

A. Radium
B. Plutonium
C. Zirconium
D. Uranium
Answer» C. Zirconium
Explanation: Zireonium is a lustrous, grey- white, strong transition metal that resembles titanium. Zirconium is mainly used as a refractory and pacifier, although it is used in small amounts as an alloying agent for its strong resistance to corrosion.

KMnO4 can be used as –

A. Insecticide
B. Fertilizer
C. Pesticide
D. Disinfectant
Answer» D. Disinfectant
Explanation: Potassium permanganate is an inorganic chemical compound with the formula KMnO4. As an oxidant, potassium permanganate can act as an antiseptic. For example, dilute solutions are used to treat canker sores (ulcers), disinfectant for the hands and treatment for mild pompholyx, dermatitis, and fungal infections of the hands or feet. Potassium permanganate is used extensively in the water treatment industry.

A thick paste of cement, sand and water is called –

A. Concrete
B. R.C.C.
C. Mortar
D. Kiln
Answer» C. Mortar
Explanation: Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. Modern mortars are typically made from a mixture of sand, a binder such as cement or lime, and water

Which one of the following metals pollutes the air of a city having large number of automobiles?

A. Cadmium
B. Chromium
C. Lead
D. Copper
Answer» C. Lead
Explanation: The history of car pollution has been one of air and water contamination followed by regulated improvement. Cars and trucks cause a lot of air the pollution in the world today, and contribute a lot to the most common and dangerous air pollutants. About 2.3 million tons of lead in lead acid (PbA) batteries is on the road now. Over 1 million tons of lead is used in making new batteries each year. In the past, motor vehicles were the biggest source of lead. But since leaded gasoline has been phased out, lead emissions have decreased by about 98 percent.

`Milk of Magnesia' is a suspension of –

A. magnesium sulphate
B. magnesium carbonate
C. magnesium hydroxide
D. magnesium chloride
Answer» C. magnesium hydroxide
Explanation: Magnesium hydroxide is an inorganic compound with the chemical formula Mg(OH)2. As a suspension in water. it is often called milk of magnesia because of its milk-like appearance.

Pollutant from motor car exhaust that causes mental disease is –

A. Lead
B. NO2
C. SO2
D. Hg
Answer» A. Lead
Explanation: Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems. It interferes with the development of the nervous system, and is therefore particularly toxic to children.

The total energy of revolving electron in an atom –

A. cannot be negative
B. can have any value above zero
C. can never be positive
D. will always be positive
Answer» C. can never be positive
Explanation: The total energy of a revolving electron in any orbit is the sum of its kinetic and potential energies. Energy of an electron at infinite distance from the nucleus is zero. As an electron approaches the nucleus, the electron attraction increaes and the energy of electron decreases and thus becomes negative. Thus, it can never be positive.

The chief source for the production of nitrogeneous fertilizers is :

A. Ammonia
B. Nitric acid
C. Nitrogen
D. Nitrogen dioxide
Answer» A. Ammonia
Explanation: Nitrogen fertilizers are often made using the Haber-Bosch process which uses natural gas for the hydrogen and nitrogen gas from the air at an elevated temperature and pressure in the presence of a catalyst to form ammonia as the end product. This ammonia is used as a feedstock for other nitrogen fertilizers, such as anhydrous ammonium nitrate and urea.

Zn + 2 HCl = H2 + ZnCl, is an example of which type of reaction?

A. Double displacement reaction
B. Combination reaction
C. Single displacement reaction
D. Decomposition reaction
Answer» C. Single displacement reaction
Explanation: This reaction is an example of single displacement reaction. In Substitution or Single Replacement Reactions, a single free element replaces or is substituted for one of the elements in a compound.

Which of the following is not a natural polymer?

A. Wool
B. Silk
C. Cotton
D. Teflon
Answer» D. Teflon
Explanation: Natural polymers occur in nature and can be extracted. They are often water- based. Examples of naturally occurring polymers are silk, wool, DNA, cellulose, cotton and proteins.

Vulcanized rubber contains sulphur –

A. 2%
B. 3-5%
C. 7-9%
D. I 0- 5%
Answer» B. 3-5%
Explanation: A vulcanized flexible tyre rubber contains about 3 -5% of sulphur whereas hard rubber (ebonite) contains about 32% of sulphur. The stiffness of vulcanized rubber depends on the amount of sulphur added.

Which of the following is a metallic ore?

A. Mica
B. Quartz
C. Feldspar
D. Galena
Answer» D. Galena
Explanation: Galena is the most abundant lead mineral. It is a metallic, lead-gray mineral with cubic cleavage and a distinctly high density. It belongs to the octahedral sulfide group of minerals with metal ions in octahedral positions.

The first organic compound synthesized in the laboratory was -

A. Urea
B. Uric acid
C. Lactic acid
D. Glucose
Answer» A. Urea
Explanation: In 1828, German chemist Friedrish Wohler synthesized first organic compound, urea in the laboratory by heating ammonium cyanate (an inorganic compound).

The green colour seen in firework displays is due to the chloride salt of–

A. Sodium
B. Strontium
C. Barium
D. Calcium
Answer» C. Barium
Explanation: The red, orange, yellow, green, blue and purple colors exploding in the night skyduring a pyrotechnic festival are created by the use of metal salts. Barium chloride provides green colour to firework displays. Metal salts that are commonly used in fire-work displays include: strontium carbonate (red), calcium chloride (orange), sodium nitrate (yellow), barium chloride (green fireworks) and copper chloride (blue fireworks).

The radiation that can penetrate deepest in our body –

A. UV-radiation
B. Alpha-particles
C. a-particles
D. Gamma-particles
Answer» D. Gamma-particles
Explanation: The ability of radioactivity to pass through materials is called its penetrating ability. Penetrating ability depends on the size of the radioactive particle. Alpha particles are the biggest, beta particles are very much smaller and gamma rays have no mass.

Which adioactive pollutant has recently drawn the attention of the public due to its occurrence in the building materials?

A. Radium
B. Radon
C. Thorium
D. Rlutonium
Answer» C. Thorium
Explanation: Thorium, a naturally occurring radioactive element, four times more abundant than uranium in the earth's crust.

Chemical properties of isotopes –

A. must be same
B. must be different
C. need not be same
D. need not be different
Answer» A. must be same
Explanation: Isotopes of an element have similar chemical properties as they have the same number of electrons as an atom of that element. The electron arrangement is the same owing to same chemical properties. However, they have different numbers of neutrons, which
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