Chemistry GK Questions Quiz-43

Chemistry GK Questions Quiz-43

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

    841. Activated Charcoal is used to remove colouring matter from pure substances by

    (1) Bleaching 
    (2) Oxidation
    (3) Adsorption 
    (4) Reduction
    Answer:
    841. (3) Heating wood to a very high temperature in the absence of air makes charcoal. When it is heated to an even higher temperature, about 930°C, impurities are driven from its surface and it becomes activated charcoal, sometimes called decolorizing charcoal. This activated charcoal can remove impurities in either the gaseous or liquid state from many solutions. It does so by the process of adsorption, or by attracting these molecules to the surface.

    842. Chernobyl disaster is the result of pollution by

    (1) Oil spill
    (2) Acid rain
    (3) Carbon dioxide
    (4) Radioactive waste
    Answer:
    842. (4) The Chernobyl disaster was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in the city of Pripyat, then located in the Ukrainian USSR. An explosion and fire released large quantities of radioactive particles into the atmosphere, which spread over much of the western USSR and Europe.

    843. Which of the following caused radioactive pollution along the coast of Kerala ?

    (1) Plutonium 
    (2) Zinc
    (3) Thorium 
    (4) Radium
    Answer:
    843. (3) Thorium-rich monazite sand deposits on the Kerala coast has been responsible for natural radioactive contamination. It has been pronounced on the southwest coastal line of the state. The region has been found to have elevated levels of background radioactivity due to high abundance of thorium.

    844. For extinguishing fire, we use

    (1) Hydrogen
    (2) Carbon Monoxide
    (3) Carbon Dioxide
    (4) Marsh gas
    Answer:
    844. (3) Fire extinguishers use carbon dioxide to displace the oxygen necessary for a fire to burn, extinguishing the blaze. Fires need oxygen, fuel, and heat to ignite, and removing any one of those three components can put out a fire. It is useful for electrical fires and some flammable liquid fires, but may make some gasoline or paper fires worse by dispersing burning material.

    845. The chemical name of quartz is

    (1) Calcium oxide
    (2) Calcium phosphate
    (3) Sodium phosphate
    (4) Sodium silicate
    Answer:
    845. (4)Quartz is a compound of one part silicon and two parts of oxygen, silicon dioxide, SiO2. Quartz is the most abundant silica mineral. It is used in a number of industries, the important being glass, foundry, sodium silicate, silicon alloys, etc. The various grades of sodium silicate are characterized by their SiO2:Na2O weight ratio.

    846. The depletion in Ozone layer is caused by ___________ .

    (1) Nitrous oxide
    (2) Carbon dioxide
    (3) Chlorofluorocarbons
    (4) Methane
    Answer:
    846. (3) Chlorofluorocarbons (CFCs), also known as Freon, cause the breakdown of the ozone layer that protects the earth from the sun’s ultraviolet (UV) radiation.In the upper atmosphere, the UV-induced breakdown of CFCs releases free, highly reactive chlorine and bromine atoms that lead to the breakdown of the stratospheric ozone layer. Owing to ozone depletion in the upper atmosphere, CFCs have been phased out under the Montreal Protocol of 1987.

    847. Phosphorus is kept in water because

    (1) its ignition temperature is very high
    (2) its ignition temperature is very low
    (3) its critical temperature is high
    (4) its critical temperature is low
    Answer:
    847. (2) The allotropic form of Phosphorus (white phosphorus) is less stable and therefore highly reactive because of angular strain in P4 molecule where the angles are only 60o. Having very low ignition temperature, it readily catches fire in air to give dense white fumes of P4O10. So it is kept in water to avoid oxidation by the oxygen present in air.

    848. Sea water is saltier than rain water because

    (1) Sea animals are salt producing
    (2) The air around the sea is saltish
    (3) Rivers wash away salts from earth and pour them into the sea
    (4) Sea beds have salt producing mines
    Answer:
    848. (3) Seawater is salty because rainwater dissolves the salt minerals found in soil and rocks as it travels through rivers and streams en route to the sea The rain that falls on the land contains some dissolved carbon dioxide from the surrounding air. This causes the rainwater to be slightly acidic due to carbonic acid. The rain physically erodes the rock and the acids chemically break down the rocks and carries salts and minerals along in a dissolved state as ions. The ions in the runoff are carried to the streams and rivers and then to the ocean which makes them salty.

    849. Even after sunset, the air near the Earth’s surface continue to receive heat due to

    (1) Insolation
    (2) Terrestrial Radiation
    (3) Conduction
    (4) Convection
    Answer:
    849. (2) Even after the sunset when the sun goes down, the incoming radiation from the sun stops, but there is still a lot of radiation that has been absorbed by the earth, which is re-radiated in form of terrestrial radiation.Energy leaving the earth’s surface i.e. terrestrial radiation heats up the atmosphere more than the incoming solar radiation i.e. insolation

    850. Trinitrotoluene is

    (1) used to melt metals
    (2) used to fuse two metals
    (3) used as an abrasive
    (4) used as an explosive
    Answer:
    850. (4) Trinitrotoluene (C6H2(NO2)3CH3), abbreviated as TNT, is sometimes used as a reagent in chemical synthesis, but it is best known as an explosive material with convenient handling properties. The explosive yield of TNT is considered to be the standard measure of bombs and other explosives.

    851. Nitrification is the biological process of converting

    (1) N2 into nitrate
    (2) N2 into nitrite
    (3) Ammonia into nitrite
    (4) Ammonia into N2
    Answer:
    851. (3)Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The transformation of ammonia to nitrite is usually the rate limiting step of nitrification.Nitrification is an important step in the nitrogen cycle in soil.

    852. Which of the process is known as nitrification?

    (1) Reaction of Nitrogen Monoxide with oxygen to form nitric acid
    (2) Reaction of nitrogen dioxide with water to form nitric acid
    (3) Conversion of ammonia to nitrites
    (4) Conversion of nitrite to nitric oxide
    Answer:
    852. (3) Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The oxidation of ammonia into nitrite is performed by two groups of organisms, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Nitrification is an important step in the nitrogen cycle in soil.

    853. The purest form of water in nature is

    (1) Rain water 
    (2) Lake water
    (3) River water 
    (4) Sea water
    Answer:
    853. (1) 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.

    854. The source of energy that causes the least global warming is

    (1) Coal
    (2) Geothermal energy
    (3) Natural Gas
    (4) Petroleum
    Answer:
    854. (2)Fossil fuels — coal, petroleum, and natural gas — are the primary culprit behind climate change. They contribute more than 80 percent of greenhouse gas emissions — and 98 percent of CO2 emissions alone. On the contrary, Geothermal energy is thermal energy generated and stored in the Earth. It is clean and sustainable.

    855. Which of the following is not a donor atom?

    (1) Phosphorus 
    (2) Antimony
    (3) Arsenic 
    (4) Aluminium
    Answer:
    855. (4)Aluminium is an acceptor atom, an impurity atom in a semiconductor, which can accept or take up one or more electrons from the crystal and become negatively charged.In semiconductor physics. It is a dopant atom that when added to a semiconductor can form a p-type region. For example, when silicon (Si), having four valence electrons, needs to be doped as a p-type semiconductor, elements from group III like boron (B) or aluminium (Al), having three valence electrons, can be used. The latter elements are also called trivalent impurities. Other trivalent dopants include indium (In) and gallium (Ga).

    856. Besides CO2, the other green house gas is

    (1) CH4 
    (2) N2 N2
    (3) Ar Ar 
    (4) O2
    Answer:
    856. (1) The greenhouse gases in Earth’s atmosphere are: Water vapour (H2O), Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Ozone (O3) and Chlorofluorocarbons (CFCs). Methane is an important greenhouse gas with a global warming potential of 34 compared to CO2 over a 100-year period, and 72 over a 20-year period.

    857. Which of the following is a commercial source of energy?

    (1) Agricultural waste
    (2) Dried dung
    (3) Sun
    (4) Natural gas
    Answer:
    857. (4) Energy is broadly classified as commercial and non-commercial energy. Firewood, agricultural waste (straw, etc.) and animals waste (cowdung) are the important components of non-commercial energy.Coal, petroleum products, natural gas and, electricity are the important components of commercial energy. These goods are largely used for commercial purposes in the factories and farms.

    858. Which of the following is a natural polymer?

    (1) Bakelite 
    (2) Nylon
    (3) Polythene 
    (4) Starch
    Answer:
    858. (4) Cotton, starch, cellulose and rubber are some of the naturally occurring polymers.Starch is a condensation polymer made up of hundreds of glucose monomers, which split out water molecules as they chemically combine. Starch is a member of the basic food group carbohydrates and is found in cereal grains and potatoes. It is also referred to as a polysaccharide, because it is a polymer of the monosaccharide glucose.

    859. Which one of the following non metals shows allotropy in the liquid state?

    (1) Carbon
    (2) Sulphur
    (3) Phosphorous
    (4) Bromine
    Answer:
    859. (2) Sulphur is a non-metal that shows allotropy in the liquid state. If sulphur is heated slowly the changes between the different forms can be observed. These changes are in the form of colour and viscosity (thickness) of the liquid. If the dark brown liquid sulphur is poured into a beaker of cold water, plastic sulphur is formed. This is an elastic, rubber-like form of sulphur.

    860. Which of the following is not a nitrogenous fetiliser?

    (1) Ammonium sulphate
    (2) Urea
    (3) Ammonium nitrate
    (4) Superphosphate
    Answer:
    860. (4) Superphosphateis a common synthetic phosphorus fertilizer. It contains phosphorus and sulphur in a ratio of 1 to 1.22.?It is produced by treatment of “phosphate rock” with acids such as sulphuric acid. Superphosphate is the principal carrier of phosphate, the form of phosphorus usable by plants, and is one of the world’s most important fertilizers.


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