Chemistry GK Questions Quiz-31

Chemistry GK Questions Quiz-31

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

    601. The name of unreactive gas is

    (1) Carbon dioxide
    (2) Hydrogen
    (3) Nitrogen
    (4) Oxygen
    Answer:
    601. (3) Nitrogen is chemically unreactive because it has a strong triple bond which binds the two nitrogen atoms together making it harder for it to be broken. It does not burn, and at ordinary temperatures it does not react with other elements.

    602. Heavy water is so called because it contains

    (1) Heavy isotope of hydrogen
    (2) Heavy isotope of oxygen
    (3) Mole number of hydrogen atoms
    (4) Mole number of oxygen atoms
    Answer:
    602. (1) Heavy water, formally called deuterium oxide, is a form of water that contains a larger than normal amount of the hydrogen isotope deuterium, (also known as "heavy hydrogen") rather than the common hydrogen-1 isotope that makes up most of the hydrogen in normal water.

    603. Glass is soluble in

    (1) H2SO4 
    (2) HClO4
    (3) HNO3
    (4) HF
    Answer:
    603. (4) Hydrofluoric acid is a highly corrosive acid, capable of dissolving many materials, especially oxides. Its ability to dissolve glass has been known since the 17th century. It is a solution of hydrogen fluoride in water and is represented by HF.

    604. Acid rain is caused by

    (1) SO2 and particulates
    (2) NO2 and particulates
    (3) CO2 and CFCs
    (4) SO2 and NO2
    Answer:
    604. (4) 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). Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids.

    605. The nuclear particle having no mass and no charge, but only spin is

    (1) proton 
    (2) neutrino
    (3) meson 
    (4) electron
    Answer:
    605. (2) Neutrinos do not carry electric charge, and have mass quite small, though non-zero. Their mass is tiny even by the standards of subatomic particles. They are electrically neutral, weakly interacting
    elementary subatomic particles with half-integer spin.

    606. In a period from Li to F, ionisation potential

    (1) cannot be predicted
    (2) increases
    (3) decreases
    (4) remains same
    Answer:
    606. (1) Ionization energy increases along a period with increase in atomic number. However, in the periodic table, going from left to right, while the Ionization Potential of Li is 5.4 eV, that of Be: 9.3 eV, B: 8.3 eV, C: 11.3 eV, N: 14.6 eV, O: 13.6 eV, and F: 17.0 eV.

    607. Which of the following metals can deposit copper from copper sulphate solution ?

    (1) Platinum 
    (2) Mercury
    (3) Iron 
    (4) Gold
    Answer:
    607. (3) The iron displaces copper from its salt, to make iron sulfate solution and deposit a thin coating of metallic copper on the surface of the metal. In general, any metal higher than copper in the “electromotive series” will displace copper from copper sulfate solution.

    608. When Arsenic atoms are added to Germanium lattice, it becomes a/an

    (1) Insulator
    (2) Superconductor
    (3) Intrinsic semiconductor
    (4) Extrinsic semiconductor
    Answer:
    608. (4) When a pentavalent (donor) impurity, like arsenic, is added to germanium, it will form covalent bonds with the germanium atoms, leaving 1 electron relatively free in the crystal structure. Pure germanium may be converted into an N-type semiconductor by “doping” it with any donor impurity having 5 valence electrons in its outer shell. Semiconductors which are doped in this manner - either with N- or P-type impurities - are referred to as EXTRINSIC semiconductors.

    609. Which among the following is used to dilute oxygen in the gas cylinders used by divers ?

    (1) Krypton 
    (2) Argon
    (3) Helium 
    (4) Neon
    Answer:
    609. (3) Helium is used to dilute the oxygen and nitrogen to reduce these affects. Helium is the gas of choice to use because it is an inert gas, is thinner, therefore more compressible than air, and its narcotic
    properties are negligible in comparison to nitrogen.

    610. Which one of the following does not form oxyacid ?

    (1) Sulphur 
    (2) Chlorine
    (3) Nitrogen 
    (4) Fluorine
    Answer:
    610. (4) Fluorine cannot form oxyacid because fluorine is more electronegative than oxygen. For oxygen to bind, it must be a positively charged ion.

    611. Exposure to mixtures of chemicals are greater than expected on the basis of effects of exposure to each chemical individually. This is known as

    (1) Additives 
    (2) Antagonism
    (3) Synergism 
    (4) Independent
    Answer:
    611. (3) When the toxic effect of the mixture is greater than that expected for the sum of individual constituent doses, which is that effects of combined doses are more-than-additive, the interactions are said to be synergistic. Conversely, when the toxic effect of the mixture is less than that expected under the dose additivity assumption, the interactions are said to be antagonistic.

    612. The filter over which sewage is sprinkled is called as

    (1) Trickling filter
    (2) Percolating filter
    (3) Contact bed
    (4) Intermittent sand filter
    Answer:
    612. (1) A trickling filter, also known as percolating filter, is an artificial bed of stone or broken brick material over which waste water or sewage is allowed to sprinkle or to trickle. It is then collected through the under drainage system.

    613. Neutrons are slowed down in a nuclear reactor by

    (1) Fissionable material
    (2) Moderator
    (3) Control rods
    (4) Cooling system
    Answer:
    613. (2) In thermal nuclear reactors, the coolant acts as a moderator that must slow down the neutrons before they can be efficiently absorbed by the fuel. It allows neutrons to slow down to energies where they can easily cause a nucleus to fission.

    614. An element of atomic no. 29 belongs to

    (1) s-block 
    (2) d-block
    (3) p-block 
    (4) f-block
    Answer:
    614. (2) Copper (Cu) has the atomic number of 29. Copper belongs to the d-block which is the collective name for Groups 3 to 12 in the periodic table. Most of the d-block elements are considered to be metals, with a common lustrous metallic appearance.

    615. Which among the following is used as a catalyst in the production of high octane fuels?

    (1) HNO3 
    (2)H2SO4
    (3) HCl 
    (4) HF
    Answer:
    615. (2) Sulfuric acid is used as a catalyst for refining and for producing alkylate, an essential component of highoctane fuel. The hydrocarbon molecules are reformed into more complex molecules with a higher octane rating value.

    616. The effect or response produced by two or more chemicals are less than the sum of the effects or response that the chemical would produce individually is known as

    (1) Antagonism
    (2) Independent
    (3) Additive
    (4) Synergism
    Answer:
    616. (1) Synergy is the interaction of multiple elements in a system to produce an effect different from or greater than the sum of their individual effects. On the other hand, antagonism is the combined action of two or more substances to produce an effect less than the sum of their individual effects.

    617. Threshold limit value of copper in the atmospheric air is

    (1) 0.001 mg/m3
    (2) 0.01 mg/m3
    (3) 1.0 mg/m3
    (4) 5.0 mg/m3
    Answer:
    617. (3) Inspirable copper dust takes a predominantly fibrous effect. The ALV of copper aerosol in the
    workplace atmosphere is 0.5 mg/m3, while the threshold limit value (TLV) is 1.0 mg/m3.

    618. Silicone is a polymer of

    (1) Tetraalkyl silane
    (2) Silicon tetrachloride
    (3) Dialkyl dichloro silane
    (4) Silane
    Answer:
    618. (3) In order to manufacture silicones, alkyl-substituted chlorosilanes are used as starting material. Since dimethylsilane contains —OH group at the end of the chain, polymerization and chain length increases. However, the hydrolysis of alkyl trichlorosilane gives very complex cross linked polymer.

    619. Which is a natural colloid ?

    (1) Sodium chloride
    (2) Urea
    (3) Cane-sugar
    (4) Blood
    Answer:
    619. (4) Examples of natural colloids can be found in our body itself: blood consists of colloidal sized red blood corpuscles (RBC) which provide the vital oxygen to all the body tissues.

    620. Which one of the following does not contain Silver ?

    (1) Ruby Silver
    (2) Lunar Caustic
    (3) German Silver
    (4) Horn Silver
    Answer:
    620. (3) Nickel silver, also known as German silver, 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.


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