Chemistry GK Questions Quiz-44

Chemistry GK Questions Quiz-44

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

    861. Bauxite is used as raw material by which industry ?

    (1) Aluminium 
    (2) Iron
    (3) Steel 
    (4) Gold
    Answer:
    861. (1) Bauxite is the principal ore of aluminium. Bauxite is not a mineral. It is a rock formed from a laterite soil that has been severely leached of silica and other soluble materials in a wet tropical or subtropical climate. Aluminium is extracted from bauxite using the Bayer process.

    862. Thermal electricity is generated by using which of these ?

    (1) Coal only
    (2) Coal and Natural Gas only
    (3) Coal, Natural Gas and Petroleum
    (4) None of these
    Answer:
    862. (3) A thermal power station is a power plant in which heat energy is converted to electric power. Thermal power is producing using fossil fuel such as coal, natural gas or petroleum. More than 65% of India’s electricity generation capacity comes from thermal power plants, with about 85% of the country’s thermal power generation being coal-based.

    863. When iron rusts, its weight

    (1) decreases
    (2) increases
    (3) remains the same
    (4) first increases and then decreases
    Answer:
    863. (2) When iron rusts, oxide compounds are formed due the interaction between oxygen in the air or in water and the metal. Because of the oxygen atoms binding with the metal, the weight of the metal with rust will increase.

    864. Silver gets corroded due to ___ in air.

    (1) Oxygen
    (2) Hydrogen Sulphide
    (3) Carbon dioxide
    (4) Nitrogen
    Answer:
    864. (2) Silver is a fairly stable metal and under normal circumstances does not corrode quickly. However, it is particularly susceptible to the effects of the sulfide radical. However, when exposed to air, silver reacts with Hydrogen Sulphide in the atmosphere, especially in marine environment, and readily forms a surface tarnish of silver sulphide. 2Ag + H2S ® Ag2S +H2

    865. Which of the following is a radioactive element?

    (1) Cobalt 
    (2) Uranium
    (3) Argon 
    (4) Chromium
    Answer:
    865. (2) Uranium (U) is a naturally occurring radioactive element. Its nucleus is unstable, so the element is in a constant state of decay, seeking a more stable arrangement. One of its isotopes, uranium-235, is the only naturally occurring isotope capable of sustaining a nuclear fission reaction.In fact, uranium was the element that made the discovery of radioactivity possible.

    866. Ozone saves the biosphere by absorbing high energy radiations called _____ .

    (1) Infra-red (IR)
    (2) Gamma rays
    (3) Ultraviolet rays (UV)
    (4) X–rays
    Answer:
    866. (3)The ozone layer or ozone shield is a region of Earth’s stratosphere that absorbs most of the Sun’s ultraviolet (UV) radiation. It absorbs 97 to 99 percent of the Sun’s medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength), which otherwise would potentially damage exposed life forms near the surface.

    867. Silica gel is a

    (1) moisturizer
    (2) flavouring agent
    (3) drying agent
    (4) delicious food
    Answer:
    867. (3)Silica gel is a drying agent, meant to remove moisture from an enclosed space. It is a granular, vitreous, porous form of silicon dioxide made synthetically from sodium silicate.Silica gel packs are found in boxes containing electronics or new shoes and inside purses or medicine bottles. The packets contain either granular silicic acid, which resembles sand, or tiny gel beads.

    868. Biofertilizers convert nitrogen to _______ .

    (1) nitrates 
    (2) ammonia
    (3) nitrogenase 
    (4) amino acids
    Answer:
    868. (2) Bio-fertilizers are micro-organisms which bring about nutrient enrichment of soil by enhancing the availability of nutrients to crops. The micro-organisms which act as bio-fertilizers are bacteria, cyanobacteria (blue green algae) and mycorrhizal fungi.The symbiotic nitrogen-fixing bacteria convert free nitrogen to ammonia, which the host plant utilizes for its development.

    869. All isotopes of the same element have ______

    (1) different atomic numbers and different atomic mass
    (2) different atomic numbers and the same atomic mass
    (3) the same atomic number but different atomic masses
    (4) the same atomic number and the atomic mass
    Answer:
    869. (3) Isotopes are forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei. So they have the same atomic number, but differ in relative atomic mass. For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon having the same atomic number of 6, but with mass numbers 12, 13 and 14 respectively.

    870. Nitric acid does not react with

    (1) Gold 
    (2) Copper
    (3) Zinc 
    (4) Iron
    Answer:
    870. (1) Concentrated nitric acid is a very strong oxidator capable of reacting with the noble metals such as copper or silver. Some precious metals, such as pure gold and platinum-group metals do not react with nitric acid. However, pure gold does react with aqua regia, a mixture of concentrated nitric acid and hydrochloric acid.

    871. In arc welding, Argon is used because of its

    (1) Low reactivity with metal
    (2) Ability to lower the melting point of the metal
    (3) High flammability
    (4) High calorific value
    Answer:
    871. (1) In arc welding, Argon is used as a shielding gas because it is chemically inert and forms no compounds. At the high temperatures that welding requires, the metals being welded become highly reactive to the elements in the atmosphere. Contamination from these elements can lead to brittle welds
    and instability in the welding arc. So,argon and other inert gases are sprayed.

    872. Inert gases are

    (1) Miscible with water
    (2) Not stable
    (3) Chemically unreactive
    (4) Chemically very active
    Answer:
    872. (3) An inert gas is a gas which does not undergo chemical reactions since their valence shells are filled, meaning they don’t normally form chemical bonds with other elements. They are extremely stable; they rarely gain, lose or share electrons.The inert gases, also called noble gases, are argon, helium, neon, krypton, xenon and radon.

    873. Chemical name of vinegar is

    (1) Acetone 
    (2) Acetic acid
    (3) Formaldehyde
    (4) Ethanol
    Answer:
    873. (2) Vinegar is roughly 3–9% acetic acid CH3COOH) by volume, making acetic acid the main component of vinegar apart from water. The acetic acid is produced by the fermentation of ethanol by acetic acid bacteria.Vinegar is mainly used as a cooking ingredient, or in pickling.

    874. Iodex, a pain relief balm, has the smell of __________ .

    (1) Methyl salicylate
    (2) Ethyl salicylate
    (3) Propyl salicylate
    (4) Butyl salicylate
    Answer:
    874. (1) Iodex has the characteristic odour of Methyl salicylate, an organic ester naturally produced by many species of plants, particularly wintergreens. It is used in high concentrations as a rubefacient and analgesic in deep heating liniments to treat joint and muscular pain.

    875. Which of the following is usually not an air-pollutant?

    (1) Hydrocarbons
    (2) Sulphur dioxide
    (3) Carbon dioxide
    (4) Nitrous oxide
    Answer:
    875. (4) The six air pollutants are carbon monoxide, lead, ground-level ozone, nitrogen dioxide, particulate matter, and sulfur dioxide.The combustion of gasoline and other hydrocarbon fuels in automobiles, trucks, and jet airplanes produces several primary air pollutants. Nitrous oxide (N2O), commonly known as laughing gas, is used in surgery and dentistry for its anaesthetic and analgesic effects.

    876. Which of the following fuels causes minimum environmental pollution?

    (1) Diesel 
    (2) Kerosene
    (3) Hydrogen 
    (4) Coal
    Answer:
    876. (3) Coal, diesel and kerosene are examples of fossil fuels that contribute to pollution. In contrast, hydrogen burns in air, it produces nothing but water vapor and energy. It is considered as totally clean and nonpolluting source of energy.

    877. Vinegar is __________ .

    (1) diluted acetic acid
    (2) glacial acetic acid
    (3) glacial formic acid
    (4) diluted formic acid
    Answer:
    877. (4) Vinegar is mostly dilute acetic acid, often produced by fermentation and subsequent oxidation of ethanol. It is roughly 3–9% acetic acid by volume, making acetic acid the main component of vinegar apart from water.

    878. What is the product formed when sodium bicarbonate is heated strongly?

    (1) Sodium Carbonate
    (2) Sodium Hydroxide
    (3) Sodium Peroxide
    (4) Sodium Monoxide
    Answer:
    878. (1) When sodium bicarbonate is strongly heated, it decomposes into sodium carbonate, water vapor, and carbon dioxide. Solid sodium carbonate is a white powder and is used in cooking under the name ‘baking powder’; sodium bicarbonate is used in baking under the name ‘baking soda’.
    2NaHCO3 (s) ® Na2CO3 (s) + CO2 (g) + H2O (g)

    879. Sullage water is –

    (1) waste water released from kitchen
    (2) waste water released from toilets
    (3) waste water released from factories
    (4) waste water released from hospitals
    Answer:
    879. (1) Sullage is a term used to describe wastewater that arises as a byproduct of daily human activities such as showering, washing kitchen utensils, and doing the laundry. It is used water that does not contain excreta. Sullage is commonly referred to as gray water that is a mixture of water, soap, detergent, bleach, dirt, and other compounds discarded after use.

    880. The most pure form of Carbon among the options is

    (1) Anthracite 
    (2) Lampblack
    (3) Graphite
    (4) Wood Charcoal
    Answer:
    880. (1) There are three forms of pure carbon: graphite, coal and diamond. Among coal, Anthracite has the highest carbon content, the fewest impurities, and the highest calorific content of all types of coal except for graphite. Anthracite is the most metamorphosed type of coal in which the carbon content is between 92.1% and 98%.

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