Chemistry GK Questions Quiz-30

Chemistry GK Questions Quiz-30

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

    581. Iodine value is used to estimate

    (1) Hydroxyl groups in oil
    (2) Alkali content in oil
    (3) Unsaturation in oil
    (4) Carboxylic groups in oil
    Answer:
    581. (3) Iodine value is used to estimate unsaturation in oil.

    582. Element 106 was discovered by

    (1) Rutherford 
    (2) Seaborg
    (3) Lawrence 
    (4) Kurchatove
    Answer:
    582. (2) Element 106 was discovered by Seaborg.

    583. The value of gas constant R in Ergs deg–1 mole–1 is

    (1) 8.314 × 107 
    (2) 8.341 × 107
    (3) 8.413 × 107 
    (4) 4.183 × 107
    Answer:
    583. (1) The universal gas constant R signifies the work done by or on a gas per mole per kelvin. The SI unit of R is J mole–1 K–1 and its value is 8.314 J mole–1K–1. In CGS unit, the value of R is 1.98 cal mol–1°C–1

    584. Which of the following metals is used in Space Crafts to withstand high temperatures ?

    (1) Fe 
    (2) Ti
    (3) Ni 
    (4) Pb
    Answer:
    584. (2) Titanium alloy, which has high corrosion resistance, high specific strength, and good heat
    resistance, is used for different spacecraft parts including outer fuel tank sheathing and wings. It is
    extremely strong at high temperatures.

    585. Brass gets discoloured in air due to constant exposure in presence of:

    (1) Aluminium phosphide
    (2) Hydrogen sulphide
    (3) Hydrogenated wafers
    (4) Aluminium sulphide
    Answer:
    585. (2) Brass gets discoloured in air because of Hydrogen sulphide. Transition elements are coloured. The brass is combination of Zn and Cu. But it is discoloured due to hydrogen sulphide in air.

    586. The fat of a common mussel-secretes a sticky glue that can be used to make heart implants. The unique chemical compound present in the glue is:

    (1) Amino phenyl alanine
    (2) Hydroxy phenyl alanine
    (3) Phenyl alanine
    (4) Dihydroxy phenyl alanine
    Answer:
    586. (4) The foot of the common mussel (Mytilus edulis) produces a sticky glue due to a unique compound called mussel adhesive protein, which contains a high concentration of an amino acid, DOPA (dihydroxyphenylalanine), which can cling to wet surfaces with extraordinary strength. Besides heart implants, the compound could be used as a tooth coating to prevent dental plaque, which is caused by bacterial infection.

    587. Nitrogen is an essential constituent of all :

    (1) Fats 
    (2) Proteins
    (3) Vitamins 
    (4) Carbohydrates
    Answer:
    587. (2) Nitrogen is a major constituent of all proteins, and thus of all living organisms. The deficiency of nitrogen causes yellowing of older leaves, stunted plants, dormancy of lateral buds, purple colouration in shoot axis surface, wrinkling of cereal grains and inhibition of cell division.

    588. Rutherford’s scattering experiment proved the presence of

    (1) atoms in all matter
    (2) electrons in atoms
    (3) neutrons in atoms
    (4) nucleus in atoms
    Answer:
    588. (4) Ernest Rutherford and his fellows Geiger and Marsden proved between 1911 and 1913 the
    existence of the atomic nucleus. This scattering experiment led to the development of the Rutherford
    model (planetary model) of the atom, and eventually to the Bohr model.

    589. When a metal is heated in a flame, the electrons absorb energy and jump to higher energy state. On coming back to the lower energy siate, they emit light, which we can observe in

    (1) Raman spectra
    (2) Absorption spectra
    (3) Emission spectra
    (4) Fluorescence
    Answer:
    589. (3) When a metal atom is strongly heated, its electrons absorb the heat energy and jump to a higher energy level. When the electron returns to its original position it gives off the energy it absorbed in the form of light. The result of all these jumps is to produce what is called an emission spectrum. An emission spectrum is a set of coloured lines that correspond to the energy the electron has released at each stage of its fall back to its original state.

    590. “Bhopal gas tragedy” 1984 is related to

    (1) Aluminium Phosphide
    (2) Methyl bromide
    (3) Methyl isocyanate
    (4) Carbon dioxide
    Answer:
    590. (3) In the Bhopal disaster which took place on 2-3 December, 1984 over 500,000 people were exposed to methyl isocyanate gas and other chemicals. The toxic substance made its way in and around the shantytowns located near the plant.

    591. The percentage of nitrogen present in ammonium sulphate is :

    (1) 27% 
    (2) 25%
    (3) 30.5% 
    (4) 18%
    Answer:
    591. (1) Ammonium sulfate, (NH4)2SO4 contains 21% nitrogen as ammonium cations, and 24% sulfur as sulfate anions. It is an inorganic salt which is most commonly used as a soil fertilizer.

    592. Ethanol containing 5% water is known as :

    (1) Dilute alcohol
    (2) Power alcohol
    (3) Rectified spirit
    (4) Absolute alcohol
    Answer:
    592. (3) A rectified alcohol is highly concentrated ethanol which has been purified by means of repeated distillation, a process that is called rectification. It typically contains 95% alcohol by volume and 5 % water. Normally, ethanol with 5 % water is known as pure alcohol.

    593. Stains of rust on clothes can be removed by :

    (1) Oxalic acid 
    (2) Petrol
    (3) Alcohol 
    (4) H2O2
    Answer:
    593. (1) Rust stains can be a challenge to remove because the stain consists of tiny iron oxide particles. Acidic solutions work best for these stains. The important ingredient in these removers is an acid - usually oxalic or hydrofluoric acid. The remover ingredients combine with the iron and loosen it from the fabric, then hold it in suspension in the wash water.

    594. Which one of the following has greatest mass ?

    (1) electron 
    (2) proton
    (3) neutron
    (4) hydrogen nucleus
    Answer:
    594. (3) Mass of proton is 1.672621777(74) × 10-27 kg. An electron has a mass 9.10938291(40) ×10-31 kg that is approximately 1/1836 that of the proton. The mass of neutron is slightly larger than that of a proton. The mass of the hydrogen nucleus is 1.7 x 10-27 kg. The heaviest of these particles is the neutron.

    595. A colloidal system in which a liquid is dispersed in a liquid is called

    (1) gel 
    (2) emulsion
    (3) sol 
    4) precipitate
    Answer:
    595. (2) An emulsion is a mixture of two or more liquids that are normally immiscible (nonmixable or
    unblendable). Emulsions are part of a more general class of two-phase systems of matter called colloids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, milk, mayonnaise, and some cutting fluids for metal working.

    596. The antiseptic compound present in dettol is

    (1) Iodine 
    (2) Enloroxylenol
    (3) Biothional 
    (4) Cresol
    Answer:
    596. (2) The active ingredient in Dettol that confers its antiseptic property is chloroxylenol (C8H9ClO), an aromatic chemical compound. Chloroxylenol comprises 4.8% of Dettol’s total mixture, with the
    rest composed of pine oil, isopropanol, castor oil soap, caramel and water.

    597. Piped Natural Gas (PNG) is used for

    (1) Mining 
    (2) Welding
    (3) Anaesthesia 
    (4) Cooking
    Answer:
    597. (4) PNG is mainly methane – CH4 with a small percentage of other higher hydrocarbons. The ratio
    of carbon to hydrogen is least in methane and hence it burns almost completely making it the cleanest fuel. Domestic PNG customers, also known as Residential customers, use gas for cooking purpose and also for heating water through gas geysers.

    598. Which metal is the heaviest in periodic table among the following ?

    (1) Os 
    (2) Pt
    (3) Pb 
    (4) W
    Answer:
    598. (1) The densest chemical element is Osmium (which is a metal). Osmium has a density of around 22 grams per cubic centimeter, about twice the density of lead.

    599. The chemical formula of the laughing gas is

    (1) NO 
    (2) N2O
    (3) NO2 
    (4) N2O3
    Answer:
    599. (2) Nitrous oxide, commonly known as laughing gas, is a chemical compound with the formula N2O. It is an oxide of nitrogen.

    600. The important metal used with iron to produce stainless steel is

    (1) Aluminium 
    (2) Chromium
    (3) Tin 
    (4) Carbon
    Answer:
    600. (2) Stainless steel is an alloy of iron with chromium. Chromium prevents its from corrosion. Stainless steel differs from carbon steel by the amount of chromium present.


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