81. The technique of chromatography is used to-

1. Identify colour substances
2. Determine the structure of substances
3. Dry distillation of colouring substances
4. Separate the substances from a mixture

Option “D” is correct
Chromatography is a separation technique used to separate the different components in a liquid mixture. The purpose of preparative chromatography is to separate the components of a mixture for more advanced use and thus a form of purification.
82. The poisonous gas accidentally released in Bhopal Gas Tragedy is –

1. Methane
2. Nitrous Oxide
3. Methyl Isocyanate
4. Cyanogen

Option “C” is correct
Bhopal gas tragedy occured on the night of 2–3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh. Over 500,000 people were exposed to methyl isocyanate (MIC) gas and other chemicals leaked from UCIL.
83. Release of which among the following is the primary reason for depletion of the ozone layer?

1. Nitrous oxide
2. Hydrogen dioxide
3. Chlorofluro carbon
4. Carbon monoxide

Option “C” is correct
The Chlorofluro carbon formed by chlorine, fluorine and carbon. They are often used as refrigerants, solvents, and for the manufacture of spongy plastics. It is the primary reason for depletion of the ozone layer.
84. Which of the following molecules is joined by a double covalent bond?

1.C L2
2.O2
3.N2
4.He

Option “B” is correct
Oxygen atom is joined by double covalent bond.
85. The common name of sodium tetraborate decahydrate is _____.

1. Epsom salt
2. Gypsum
3. Borax
4. Galena

Option “C” is correct
The common name of Sodium Tetraborate Decahydrate is Borax.
86. Who invented Antibiotics?

1. Joseph Lister
2. William Harvey
3. Robert Knock
4. Alexander Fleming

Option “D” is correct
Antibiotics also called antibacterials, are a type of antimicrobial drug used in the treatment and prevention of bacterial infections. Alexander Fleming invented Antibiotic.
87. The Chemical formula of Methanol is _____.

1. C2HsOH
2.CH3(OH)2
3.CH3OH
4.CH4OH

Option “C” is correct
Methanol is the simplest alcohol, being only a methyl group linked to a hydroxyl group. It is a light, volatile, colorless, flammable liquid with a distinctive odour very similar to that of ethanol (drinking alcohol). However, unlike ethanol, methanol is highly toxic and unfit for consumption. Chemical formula of Methanol is CH3OH.
88. The gas usually filled in the electric bulb with Argon is –

1. Nitrogen
2. Hydrogen
3. Carbon dioxide
4. Oxygen

Option “A” is correct
Nitrogen gas is usually filled in electric bulb in a small amount with Argon Gas.
89. Which one of the following metals is accessed in the native state?

1. Aluminium
2. Gold
3. Chromium
4. Zinc

Option “B” is correct
Among the metals, gold is the least reactive, so it can be accessed in the native (free) state.
90. Which one of the following was used as a chemical weapon in the First World War?

1. Carbon monoxide
2. Hydrogen cyanide
3. Mustard gas
4. Water gas

Option “C” is correct
Mustard gas or Sulphur mustard is a chemical compound which has been used as a chemical weapon in First World War.
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11 thoughts on “Chemistry”

  6. Dolly

    I Love chemical…it’s my favourite subject..mere iss mein se hmesha hi boht ache marks aate hai….and my interest is also in chemistry…

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