McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: General Knowledge (GK) .
| 201. |
Gunpowder consits of a mixture of – |
| A. | sand and TNT |
| B. | TNT and charcoal |
| C. | nitre, sulphur and charcoal |
| D. | sulphur, sand and charcoal |
| Answer» C. nitre, sulphur and charcoal | |
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Explanation: Gunpowder, also known since the late 19th century as black powder, was the first chemical explosive and the only one known until the mid-1800s. It is a mixture of sulfur, charcoal, and potassium nitrate (saltpetre)— with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer. Because of its burning properties and the amount of heat and gas volume that it generates, gunpowder has been widely used as a propellant in firearms and as a pyrotechnic composition in fireworks. |
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| 202. |
Litmus is obtained from – |
| A. | a bacterium |
| B. | a fungus |
| C. | an alga |
| D. | lichen |
| Answer» D. lichen | |
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Explanation: Litmus is a water-soluble mixture of different dyes extracted from lichens, especially Roccellatinctoria. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic (i.e. alkaline) conditions, with the colour change occurring over the pH range 4.5-8.3 at 25 degree C. Neutral litmus paper is purple. Litmus can also be prepared as an aqueous solution that functions similarly |
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| 203. |
Vinegar made by fermentation from cane sugar contains – |
| A. | palmitic acid |
| B. | lactic acid |
| C. | citric acid |
| D. | acetic acid |
| Answer» D. 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, but historically, as the most easily available mild acid, it had a great variety of industrial, medical, and domestic uses, some of which (such as a general household cleanser) are still promoted today. Commercial vinegar is produced either by fast or slow fermentation processes. |
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| 204. |
Which of the following can be used to absorb neutrons to control the chain reaction during nuclear fission? |
| A. | Boron |
| B. | Heavy water |
| C. | Uranium |
| D. | Plutonium |
| Answer» A. Boron | |
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Explanation: Boron shielding is used as a control for nuclear reactors, taking advantage of its high cross-section for neutron capture. Elemental boron is rare and poorly studied because the material is extremely difficult to prepare. Most studies on "boron" involve samples that contain small amounts of carbon. Chemically, boron behaves more similarly to silicon than to aluminium. Crystalline boron is chemicallyinert and resistant to attack by boiling hydrofluoric or hydrochloric acid. |
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| 205. |
Bone ash contains - |
| A. | Calcium sulphate |
| B. | Phosphoric sulphate |
| C. | Calcium phosphate |
| D. | Calcium hypophosphate |
| Answer» C. Calcium phosphate | |
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Explanation: Bone ash is a. white material produced by the calcination of bones. It is primarily composed of calcium phosphate. It is commonly used in fertilizers, polishing compounds and in making ceramics such as bone china. It also has historical uses in the manufacture of baking powders and assay cupels. |
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| 206. |
The hardest substance available in earth is – |
| A. | Platinum |
| B. | Silicon |
| C. | Diamond |
| D. | Gold |
| Answer» C. Diamond | |
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Explanation: Diamond is the hardest naturally occurring substance found on Earth. But it is not the hardest substance. |
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| 207. |
potato tuber has been cut into two halves. A few drops of iodine solution are placed on the cut surface of one of the halves. What colour change will be noticed? |
| A. | From brown to blue-black |
| B. | From brown to orange-red |
| C. | From blue to pink |
| D. | From pink to blue-green |
| Answer» A. From brown to blue-black | |
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Explanation: The Iodine test is used to test for the presence of starch. Iodine solution — iodine dissolved in an aqueous solution of potassium iodide — reacts with the starch producing a purple black colour. |
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| 208. |
Lead pencil contains – |
| A. | lead |
| B. | ferrous sulphide |
| C. | lead sulphide |
| D. | graphite |
| Answer» D. graphite | |
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Explanation: 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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| 209. |
Solder is an alloy of – |
| A. | lead, zinc |
| B. | copper, lead |
| C. | tin, lead |
| D. | sodium, lead |
| Answer» C. tin, lead | |
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Explanation: Tin/lead solders, also called soft solders, are commercially available with tin concentrations between 5% and 70% by weight. The greater the tin concentration, the greater the solder's tensile and shear strengths. Alloys commonly used for electrical soldering are 60/40 Tin/lead (Sn/Pb) which melts at 370 °F or 188 °C and 63/37 Sn/Pb used principally in electrical/electronic work. |
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| 210. |
What is the most common salt in sea water? |
| A. | Calcium carbonate |
| B. | Potassium chloride |
| C. | Sodium chloride |
| D. | Magnesium sulphate |
| Answer» C. Sodium chloride | |
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Explanation: Sodium chloride, also known as salt, common salt, table salt or halite, is an ionic compound with the formula NaCl, representing equal proportions of sodium and chloride. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multi-cellular organisms. |
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| 211. |
When quick lime is added to water |
| A. | heat is liberated |
| B. | heat is absorbed |
| C. | temperature decreases |
| D. | no heat change takes place |
| Answer» A. heat is liberated | |
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Explanation: When quick lime is added to water, then a chemical reaction takes places and slaked lime is formed, evolving heat in this process. It makes the water boil. |
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| 212. |
The umber of neutrons present in an element having mass number 226 and atomic number 88 is– |
| A. | 88 |
| B. | 138 |
| C. | 314 |
| D. | 50 |
| Answer» B. 138 | |
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Explanation: The mass number is a count of the number of particles in an atom's nucleus which is made up of protons and neutrons. In other words, Mass Number = Number of Protons + Number of Neutrons. The atomic number is the number of protons in an atom of an element, 226 = 88 + number of Neutrons. So, the number of neutrons= 226 - 88= 138. |
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| 213. |
The atomic number of hydrogen is 1. This implies that it contains in its K- shell. |
| A. | One neutron |
| B. | One proton |
| C. | One electron |
| D. | None of the above |
| Answer» C. One electron | |
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Explanation: This implies that Hydrogen has one electron in its K shell. Also, it requires one more electron to fill the K shell. So two hydrogen atoms share their electrons to form a molecule of hydrogen, H2. |
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| 214. |
Name two elements that find wide application in transistor industry – |
| A. | Silicon and Germanium |
| B. | Carbon and Platinum |
| C. | Iridium and Germanium |
| D. | Tungsten and Platinum |
| Answer» A. Silicon and Germanium | |
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Explanation: A transistor is a semiconductor device used to amplify and switch electronic signals and electrical power. Semiconductor material (date first used): the metalloids germanium (1947) and silicon (1954) — in amorphous, polycrystalline and mono- crystalline form; the compounds gallium arsenide (1966) and silicon carbide (1997), the alloy silicon-germanium (1989), the allotrope of carbon graphene (research ongoing since 2004), etc. |
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| 215. |
The energy of the sun is mainly due to |
| A. | nuclear fission |
| B. | radioactivity |
| C. | heat |
| D. | nuclear fusion |
| Answer» D. nuclear fusion | |
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Explanation: The Sun is a main-sequence star, and thus generates its energy by nuclear fusion of hydrogen nuclei into helium. Nuclear fusion is a nuclear reaction in which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. During this process, matter is not conserved because some of the mass of the fusing nuclei is converted to photons which are released through a cycle that even our sun uses. |
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| 216. |
Tear gas used by the police to disperse the mob contains - |
| A. | Carbon dioxide |
| B. | Chlorine |
| C. | Ammonia |
| D. | Hydrogen sulphide |
| Answer» B. Chlorine | |
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Explanation: Tear gas, formally known as a lachrymatory agent, is a possibly lethal chemical weapon that stimulates the corneal nerves in the eyes to cause tears, pain, and even blindness. |
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| 217. |
Epsom salt is used - |
| A. | as purgative |
| B. | in softening water |
| C. | in paper industry |
| D. | in making tooth paste |
| Answer» A. as purgative | |
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Explanation: Magnesium sulfate is an inorganic salt (chemical compound) containing magnesium, sulfur and oxygen which is commonly called Epsom Salt. Because like other salts, it withdraws water from cells, Epsom salt is used as a fast-acting purgative in some types of poisoning, to draw water into the intestines, thus, reducing constipation; to withdraw toxins from the body; and to draw fluid from the brain in cases of cerebral edema. |
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| 218. |
The ratio of pure gold in 18 carat gold is - |
| A. | 100% |
| B. | 80% |
| C. | 75% |
| D. | 60% |
| Answer» C. 75% | |
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Explanation: The gold content of alloys is measured in carats (k). Pure gold is designated as 24k where the ratio of pure gold is supposed to be 100 per cent. So 18 k gold will have pure gold ratio of 75 per cent. |
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| 219. |
Oil of vitriol is - |
| A. | nitric acid |
| B. | sulfuric acid |
| C. | hydrochloric acid |
| D. | phosphoric acid |
| Answer» B. sulfuric acid | |
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Explanation: Sulfuric acid or was called "oil of vitriol" by medieval European alchemists because it was prepared by roasting "green vitriol" in an iron retort. |
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| 220. |
The number of electrons in the outer shell of the most stable or inert atoms is |
| A. | 1 |
| B. | 5 |
| C. | 3 |
| D. | 8 |
| Answer» D. 8 | |
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Explanation: The innermost shell has a maximum of two electrons, but the next two electron shells can each have a maximum of eight electrons. |
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| 221. |
Supersonic jet causes pollution by thinning of - |
| A. | O3 layer |
| B. | O2 layer |
| C. | SO2 layer |
| D. | CO2 layer |
| Answer» A. O3 layer | |
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Explanation: Three forms (or allotropes) of oxygen are involved in the ozone-oxygen cycle: oxygen atoms (O or atomic oxygen), oxygen has (O2 or diatomic oxygen), and ozone gas (O3 or triatomic oxygen). Ozone is formed in the stratosphere when oxygen molecules photodissociate after absorbing an ultraviolet photon whose wavelength is shorter than 240 nm. This converts a single O2 into two atomic oxygen radicals. The atomic oxygen radicals then combine with separate O2 molecules to create two O3 molecules. |
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| 222. |
Photoxidation process is initiated by – |
| A. | light |
| B. | heat |
| C. | oxygen |
| D. | catalyst |
| Answer» A. light | |
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Explanation: Oxidation is a process in which something (an atom or molecule or substance) loses an electron to something else. Photo- oxidation is therefore the process of oxidation which is caused by shining light on it. Often, light can be used to cause reactions to happen, such as oxidation. The term "photo" comes from "photon" which is light. The effect is facilitated by radiant energy such as UV or artificial light. This process is the most significant factor in weathering of polymers. |
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| 223. |
Ultraviolet radiation striking the earth is due to the depletion of – |
| A. | carbon monoxide |
| B. | carbon dioxide |
| C. | ozone |
| D. | oxygen |
| Answer» C. ozone | |
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Explanation: Ozone is a powerful oxidant (far more so than dioxygen) and has many industrial and consumer applications related to oxidation. This same high oxidizing potential, however, causes ozone to damage mucus and respiratory tissues in animals, and also tissues in plants, above concentrations of about 100 parts per billion. This makes ozone a potent respiratory hazard and pollutant near ground level. |
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| 224. |
In nuclear reactors, graphite is used as a/an – |
| A. | fuel |
| B. | lubricant |
| C. | moderator |
| D. | insulator |
| Answer» C. moderator | |
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Explanation: A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid (water or gas), which runs through turbines that power either ship's propellers or generators. Some produce isotopes for medical and industrial use, and some are run only for research. In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235. |
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| 225. |
Sea water can be purified by the process of – |
| A. | distillation |
| B. | evaporation |
| C. | filtration |
| D. | fractional distillation |
| Answer» A. distillation | |
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Explanation: The traditional process used in desalination operations is vacuum distillation— essentially the boiling of water at less than atmospheric pressure and thus a much lower temperature than normal. This is because the boiling of a liquid occurs when the vapor pressure equals the ambient pressure and vapor pressure increases with temperature. |
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| 226. |
Which is/ are the important raw materials in cement industry? |
| A. | Limestone |
| B. | Gypsum and Clay |
| C. | Clay |
| D. | Limestone and Clay |
| Answer» D. Limestone and Clay | |
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Explanation: Limestone Claimed Clay Cement is a low-carbon alternative to the standard Portland cement. LC3 can reduce CO2 emissions related to cement manufacturing of cement by reducing the amount of clinker, replacing it with limestone and claimed clays. |
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| 227. |
The father of modern chemistry is – |
| A. | Priestley |
| B. | Lavoisier |
| C. | Dalton |
| D. | Mendeleeff |
| Answer» B. Lavoisier | |
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Explanation: Antoine Lavoisier was a French nobleman and chemist central to the 18th- century chemical revolution and a large influence on both the history of chemistry and the history of biology. |
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| 228. |
The acid rain destroys vegetations because it contains – |
| A. | nitric acid |
| B. | ozone |
| C. | carbon monoxide |
| D. | sulphuric acid |
| Answer» D. sulphuric acid | |
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Explanation: Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals, and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxides, which react with the water molecules in the atmosphere to produce acids. Governments have made efforts since the 1970s to reduce the release of sulfur dioxide into the atmosphere with positive results. |
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| 229. |
Diamonds are glittering and attractive because light incident on them undergoes – |
| A. | highest refraction |
| B. | multiple internal reflections |
| C. | multiple surface reflections |
| D. | hundred percent transmission |
| Answer» B. multiple internal reflections | |
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Explanation: Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Combined with wide transparency', this resultsin the clear, colourless appearance of most natural diamonds. Small amounts of defects or impurities (about one per million of lattice atoms) colour diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red. |
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| 230. |
Which of the following is a supercooled liquid? |
| A. | Ice Cream |
| B. | Teflon |
| C. | Glass |
| D. | Mercury |
| Answer» C. Glass | |
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Explanation: Most of us think as glass as a solid material, but it is actually a super cooled liquid. Molecular units have a disordered arrangement yet still have sufficient cohesion that mechanical rigidity is produced. Glass was first made in the Middle East, approximately during the third millennium BC. Early uses were primarily for vessels or decoration. |
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| 231. |
On heating, Gypsum loses certain percentage of its water content and becomes |
| A. | Chalk |
| B. | Calcium sulphate |
| C. | Plaster of Paris |
| D. | a pearl |
| Answer» C. Plaster of Paris | |
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Explanation: Plaster of paris, quick-setting gypsum plaster consisting of a fine white powder (calcium sulfate hemihydrate), which hardens when moistened and allowed to dry. |
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| 232. |
What is the element required for solar energy conversion? |
| A. | Beryllium |
| B. | Tantalum |
| C. | Silicon |
| D. | Ultra pure carbon |
| Answer» C. Silicon | |
| Explanation: The most prevalent bulk material for solar cells is crystalline silicon (abbreviatedas a group as c-Si), also known as "solar grade silicon". Bulk silicon is separated into multiple categories according to crystallinity and crystal size in the resulting ingot, ribbon, or wafer. | |
| 233. |
What is the chemical name for `Baking Soda'? |
| A. | Sodium carbonate |
| B. | Sodium bicarbonate |
| C. | Sodium nitrite |
| D. | Sodium nitrate |
| Answer» B. Sodium bicarbonate | |
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Explanation: Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula NaHCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). |
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| 234. |
The first metal used by a man was – |
| A. | Copper |
| B. | Silver |
| C. | Bronze |
| D. | Brass |
| Answer» A. Copper | |
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Explanation: Copper occurs naturally as native copper and was known to some of the oldest civilizations on record. It has a history of use that is at least 10,000 years old, and estimates of its discovery place it at 9000 BC in the Middle East; a copper pendant was found in northern Iraq that dates to 8700 BC. There is evidence that gold and meteoric iron (but not iron smelting) were the only metals used by humans before copper. |
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| 235. |
Which of the following is used to remove rust stains on cloth? |
| A. | Kerosene |
| B. | Lime |
| C. | Oxalic acid solution |
| D. | Petrol |
| Answer» C. Oxalic acid solution | |
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Explanation: Oxalic acid is an organic compound with the formula H2C2O2. It is a colourless crystalline solid that dissolves inwater to give colourless solutions. It is classified as a dicarboxylic acid. In terms of acid strength. it is much stronger than acetic acid. Oxalic acid is a reducing agent and its conjugate base, known as oxalate , is a chelating agent for metal cations. |
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| 236. |
The substance most commonly used as a food preservative is – |
| A. | sodium carbonate |
| B. | tartaric acid |
| C. | acetic acid |
| D. | sodium salt of benzoic acid |
| Answer» D. sodium salt of benzoic acid | |
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Explanation: A preservative is a naturally occurring or synthetically produced substance that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical changes. Preservative food additives can be used alone or in conjunction with other methods of food preservation. Preservatives may be antimicrobial preservatives, which inhibit the growth of bacteria or fungi, including mold or they can be antioxidants such as oxygen absorbers, which inhibit the oxidation of food constituents. |
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| 237. |
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 | |
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Explanation: Artificial rain is produced by spraying clouds with substances like Silver Iodide (costly) or cheaper ones like solid carbon dioxide (dry ice) or even finely powdered Sodium Chloride. |
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| 238. |
Detergents clean surfaces on the principle of – |
| A. | viscosity |
| B. | surface tension |
| C. | elasticity |
| D. | floatation |
| Answer» B. surface tension | |
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Explanation: Detergents and soaps are used for cleaning because pure water can't remove oily, organic soiling. Soap cleans by acting as an emulsifier. Basically, soap allows oil and water to mix so that oily grime can be removed during rinsing. Detergents were developed in response to the shortage of the animal and vegetable fats used to make soap during World War I and World War II. Detergents are primarily surfactants, which could be produced easily from petrochemicals. |
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| 239. |
Which of the following is ozone depleting pesticide? |
| A. | D.D.T. |
| B. | Benzene |
| C. | Methyl bromide |
| D. | Ethylene ozonide |
| Answer» C. Methyl bromide | |
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Explanation: Methyl bromide- is considered to be a significant ozone depleting substance (ODS) by atmospheric scientists. While methyl bromide is a natural substance, the additional methyl bromide added to the atmosphere by humans contributes to the thinning of the ozone layer, allowing increased UV radiation to reach the earth's surface, with potential impact not only to human health and the environment, but to agricultural crops as well. |
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| 240. |
Galvanised iron is made by coating iron with – |
| A. | Zinc |
| B. | Nickel |
| C. | Chromium |
| D. | Sulphur |
| 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, Although galvanization can be done with electrochemical and electro-deposition processes, the mostcommon method in current use is hot-dip galvanization, in which steel parts are submerged in a bath of molten zinc. |
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| 241. |
An atomic pile is used for – |
| A. | producing X-rays |
| B. | conducting nuclear fission |
| C. | coducting thermonuclear fusion |
| D. | accelerating atoms |
| Answer» B. conducting nuclear fission | |
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Explanation: An atomic pile is a nuclear reactor that uses controlled nuclear fission to generate energy. The most common reactor consists of a large assembly of graphite (an allotropic form of carbon) blocks having rods of uranium metal (fuel). |
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| 242. |
Which of the following type of coal has the lowest proportion of volatile matter? |
| A. | Lignite |
| B. | Peat |
| C. | Bituminous |
| D. | Anthracite |
| Answer» D. Anthracite | |
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Explanation: Anthracite has the lowest proportion of volatile matter. Volatile matter in coal refers to the components of coal, except for moisture, which are liberated at high temperature in the absence of air. This is usually a mixture of short and long chain hydrocarbons, aromatic hydrocarbons and some sulfur. The volatile matter of coal is determined under rigidly controlled standards. |
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| 243. |
The compound to which H2 does not add is – |
| A. | Biphenyl ethylene |
| B. | Tetraphenyl ethylene |
| C. | Tetra - a - naphthylethylene |
| D. | Tetra - 9 - phenanthrylethylene |
| Answer» B. Tetraphenyl ethylene | |
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Explanation: While H2 is not very reactive under standard conditions, it does form compounds with most elements. Millions of hydrocarbons are known, but they are notformed by the direct reaction of elementary hydrogen and carbon. Hydrogen can form compounds with elements that are more electronegative, such as halogens. Hydrogen forms a vast array of compounds with carbon. |
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| 244. |
Major gaseous pollutant of the thermal power station is – |
| A. | H2S |
| B. | NH3 |
| C. | NO2 |
| D. | SO2 |
| Answer» D. SO2 | |
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Explanation: A flue-gas stack is a type of chimney, a vertical pipe, channel or similar structure through which combustion product gases called flue gases are exhausted to the outside air. Flue gases are produced when coal, oil, natural gas, wood or any other fuel is combusted in an industrial furnace, a power plant's steam-generating boiler, or other large combustion device. Flue was is usually composed of carbon dioxide (CO2) and water vapor as well as nitrogen and excess oxygen remaining from the intake combustion air. |
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| 245. |
The process of removing calcium and magnesium from hard water is known as – |
| A. | Sedimentation |
| B. | Filtration |
| C. | Flocculation |
| D. | Water softening |
| Answer» D. Water softening | |
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Explanation: Water softening is the reduction of the concentration of calcium, magnesium, and certain other metal cations in hard water. Hardness ions dissolved in water can cause a variety of undesired effects including interfering with the action of soaps, the buildup oflimescale, which can foul plumbing, and galvanic corrosion. Conventional water-softening appliances intended for household use depend on an ion-exchange resin in which hardness ions are exchanged for sodium ions. |
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| 246. |
Which of the following metals causes Itai-Itai disease? |
| A. | Cadmium |
| B. | Chromium |
| C. | Cobalt |
| D. | Copper |
| Answer» A. Cadmium | |
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Explanation: Itai-itai disease was the documented case of mass cadmium poisoning in Toyama Prefecture, Japan, starting around 1912. The cadmium poisoning caused softening of the bones and kidney failure. The disease is named for the severe pains caused in the joints and spine. The cadmium was released into rivers by mining companies in the mountains. The mining companies were successfully sued for the damage. Itai-itai disease is known as one of the Four Big Pollution Diseases of Japan. |
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| 247. |
Which is used in preparation of dynamite? |
| A. | glycerol |
| B. | ethyl alcohol |
| C. | methyl alcohol |
| D. | glycol |
| Answer» A. glycerol | |
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Explanation: Dynamite is an explosive made of nitroglycerin, sorbents (such as powdered shells or clay) and stabilizers. It was invented by the Swedish chemist and engineer Alfred Nobel in Geesthacht, and patented in 1867. |
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| 248. |
Vinegar is the trade name of - |
| A. | acetic acid |
| B. | chloroform |
| C. | carbon tetrachloride |
| D. | ethyl alcohol |
| Answer» A. acetic acid | |
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Explanation: The trivial name acetic acid is the most commonly used and preferred IUPAC name. The systematic name ethanoic acid, a valid IUPAC name, is constructed according to the substitutive nomenclature. |
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| 249. |
Acid secretion is characteristic of - |
| A. | Buccal cavity |
| B. | Stomach |
| C. | Small intestine |
| D. | Large intestine |
| Answer» B. Stomach | |
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Explanation: The stomach is famous for its secretion of hydrochloric acid. It is secreted from parietal cells into the lumen where it establishes an extremely acidic environment. This acid is important for activation of pepsinogen and inactivation of ingested microorganisms such as bacteria. |
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| 250. |
Which one of the following is not a fertilizer? |
| A. | Ammonium sulphate |
| B. | Calcium sulphate |
| C. | Calcium ammonium nitrate |
| D. | Potassium nitrate |
| Answer» B. Calcium sulphate | |
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Explanation: Calcium sulfate is a common laboratory and industrial chemical. In the form of -anhydrite (the nearly anhydrous form), it is used as a desiccant. It is also used as a coagulant in products like tofu. The main sources of calcium sulfate are naturally occurring gypsum and anhydrite which occur at many locations worldwide as evaporites. |
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