Chemistry GK Questions Quiz-18

Chemistry GK Questions Quiz-18

Chemistry Multiple Choice Questions (MCQs) Quiz for State and UPSC Civil Services Examinations. Objective Questions on Chemistry for competitive examinations.

    341. The gas which is mainly responsible for the green house effect is:

    (1) Ozone
    (2) Oxygen
    (3) Carbon dioxide
    (4) Carbon monoxide
    Answer:
    341. (3) 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.

    342. Which one of the following is used for dating very old objects of archaeological importance?

    (1) Phosphorus-31
    (2) Tritium
    (3) Radium
    (4) Carbon-14
    Answer:
    342. (4) Radiocarbon dating (usually referred to as simply carbon dating) is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. After plants die or they are consumed by other organisms (for example, by humans or other animals), the incorporation of all carbon isotopes, including 14C, stops. Thereafter, the concentration (fraction) of 14C declines at a fixed exponential rate due to the radioactive decay of 14C.

    343. The main constituent of natural gas is

    (1) Methane 
    (2) Ethane
    (3) Butane 
    (4) Propane
    Answer:
    343. (1) Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, with other hydrocarbons, carbon dioxide, nitrogen and hydrogen sulfide. It is found in deep underground natural rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates. Petroleum is also another resource found in proximity to and with natural gas.

    344. Domestic cooking gas consists mostly of

    (1) methane and ethane
    (2) liquified butane and isobutane
    (3) hydrogen and acetylene
    (4) ethylene and carbon monoxide
    Answer:
    344. (2) Domestic gas is another name for Liquefied Petroleum Gas (LPG). Varieties of LPG bought and sold include mixes that are primarily propane (C3H8), primarily butane (C4H10) and, most commonly, mixes including both propane and butane, depending on the season — in winter more propane, in summer more butane.

    345. Chemically ‘Quick Silver is known as

    (1) Mercury 
    (2) Silver
    (3) Gold 
    (4) Copper
    Answer:
    345. (1) 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.

    346. Extensively used nitrogenous fertilizer is

    (1) Ammonium nitrate
    (2) Urea
    (3) Ammonium sulphate
    (4) Nitro-lime
    Answer:
    346. (2) 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.

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

    (1) Zinc 
    (2) Chromium
    (3) Lead 
    (4) Antimony
    Answer:
    347. (1) 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.

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

    (1) Methane 
    (2) Nitrogen
    (3) Helium 
    (4) Hydrogen
    Answer:
    348. (2) For some diving, gas 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), which is 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.

    349. What particles move around the nucleus of an atom and are negatively charged?

    (1) Electrons 
    (2) Protons
    (3) Positrons 
    (4) Neutrons
    Answer:
    349. (1) Circling around outside the nucleus are tiny little particles called electrons. Electrons have a negative charge. Electrons spin as they circle the nucleus billions of times every second. They are arranged in energy levels around the nucleus. When electrons gain or lose energy, they jump between energy levels as they are rotating around the nucleus.

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

    (1) Gold 
    (2) Silver
    (3) Sodium 
    (4) Copper
    Answer:
    350. (1) Gold is the least reactive in the reactivity series. Since it does not react with other elements, it is found in a free form. Only gold, silver, copper and the platinum metals occur in nature in larger amounts. Non-metallic elements occurring in the native state include carbon and sulfur.

    351. Hardest allotrope of carbon is

    (1) diamond 
    (2) graphite
    (3) coke 
    (4) lamp black
    Answer:
    351. (1) 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.

    352. The depletion of ozone layer is due to

    (1) chloro fluoro carbon
    (2) carbon dioxide
    (3) sulphur dioxide
    (4) ethane
    Answer:
    352. (1) 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-410A) by the Montreal Protocol because they contribute to ozone depletion in the upper atmosphere.

    353. Name the particle that is most essential to continue the chain reaction during the fission of uranium-

    (1) Electron 
    (2) Proton
    (3) Neutron 
    (4) Positron
    Answer:
    353. (3) Nuclear fission is either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts (lighter nuclei), often producing free neutrons and photons (in the form of gamma rays), and releasing a very large amount of energy, even by the energetic standards of radioactive decay. Fission as encountered in the modern world is usually a deliberately produced man-made nuclear reaction induced by a neutron.

    354. Which one amongst the following is not a Green House gas?

    (1) Nitrogen
    (2) Carbon dioxide
    (3) Carbon Monoxide
    (4) Chloro fluoro carbons
    Answer:
    354. (1) A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. The primary greenhouse gases in the Earth's atmosphere are water vapour, carbon dioxide, methane, nitrous oxide, and ozone.

    355. In vulcanisation process, rubber can be hardened by adding

    (1) Nitrogen 
    (2) Silicon
    (3) Sulphur 
    (4) Alcohol
    Answer:
    355. (3) In order to give more strength and more elasticity, natural rubber is heated with sulphur or sulphur compounds at 150°C temperature. Vulcanized rubber has good tensile strength.

    356. Urea is a

    (1) Sodium fertilizer
    (2) Phosphatic fertilizer
    (3) Nitrogenous fertilizer
    (4) Potassium fertilizer
    Answer:
    356. (3) 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.

    357. Conversion of chemical energy into electrical energy occurs in

    (1) Atomic bombs
    (2) Dynamo
    (3) A battery
    (4) Electric heaters
    Answer:
    357. (3) A battery is a form of chemical energy that can be converted to electrical energy. it is a device consisting of one or more electrochemical cells which performs this action. The first battery (or "voltaic pile") was invented in 1800 by Alessandro Volta.

    358. The fuel that is used in modern submarines is

    (1) Nuclear fuel 
    (2) Petrol
    (3) Coal 
    (4) Diesel
    Answer:
    358. (1) Nuclear power is now used in all large submarines, but due to the high cost and large size of nuclear reactors, smaller submarines still use diesel-electric propulsion. The ratio of larger to smaller submarines depends on strategic needs. The US Navy, French Navy, and the British Royal Navy operate only nuclear submarines.

    359. The basic chemical building block of natural rubber obtained from trees is

    (1) Isoprene 
    (2)Vinyl Chloride
    (3) Acetylene 
    (4)Neoprene
    Answer:
    359. (1) Isoprene was first isolated by thermal decomposition of natural rubber. About 95% of
    isoprene production is used to produce cis-1,4- polyisoprene—a synthetic version of natural rubber.
    Natural rubber consists mainly of poly-cis-isoprene with a molecular weight of 100,000 to 1,000,000.

    360. The name of plastic polymer from which combs, toys, bowls etc., can be made, is

    (1) Polyurethane
    (2) Polystyrene
    (3) Metallic polysulphides
    (4) Teflon
    Answer:
    360. (2) Polystyrene is an synthetic aromatic polymer made from the monomer styrene, a liquid petrochemical. It is one of the most widely used plastics. Uses include protective packaging (such as packing peanuts and CD and DVD cases), containers (such as "clamshells"), lids, bottles, trays, tumblers, and disposable cutlery.


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