Chemistry

471. In atom, neutron was discovered by:

1. J.J. Thomson
2. Chadwick
3. Rutherford
4. Newton

Option “2” is correct.
Neutron is a neutral particle which has no electrical charge. It was discovered by Chadwick in 1932.
472. To avoid ‘knocking’ of the engine of a car, which one of the following is used as an anti-knocking agent?

1. Ethyl alcohol
2. Butane
3. Tetra Ethyl Lead
4. White Petrol

Option “3” is correct.
Tetraethyl Lead (CH3CH2)4Pb is the chief antiknock agent for automotive gasoline or petrol.
473. In a car battery, electrolyte substance used is-

1. Hydrochloric acid
2. Sulphuric acid
3. Nitric acid
4. Distilled water

Option “2” is correct.
Electrolyte substance used in a car battery is Sulphuric acid (H_2 SO_4 ). It is a strong acid.
474. ‘Nobel Oil’ is the name of which one of the following explosives?

1. TNG
2. TNP
3. TNA
4. TNT

Option “1” is correct.
Tri Nitro Glycerin (TNG) also known as Nobel Oil, is an explosive fluid.
475. Which of the following fossil fuels in the cleanest fuel?

1. Coal
2. Petrol
3. Natural gas
4. Diesel

Option “3” is correct.
The use of natural gas in power generation provides a cleaner alternative to coal and other fossil fuels.
476. Which gas is mixed with Oxygen for respiration by divers in deep sea?

1. Helium
2. Nitrogen
3. Xenon
4. Ammonia

Option “1” is correct.
Heliox is a breathing gas composed of a mixture of Helium (He) and Oxygen  This is frequently used for respiration by divers in the deep sea.
477. The atomic nucleus was discovered by:

1. Rutherford
2. Dalton
3. Einstein
4. Thompson

Option “1” is correct.
The nucleus is a very dense region consisting of protons and neutrons at the centre of an atom. It was discovered in 1911 as a result of Ernest Rutherford’s interpretation of the 1909 Geiger-Marsden gold foil experiment.
478. Which one of the following mixtures is homogeneous?

1. Starch and sugar
2. Methanol and water
3. Graphite and charcoal
4. Calcium carbonate and calcium bicarbonate

Option “2” is correct.
A mixture of methanol (a liquid) and water (a liquid) is homogeneous.
479. Polymer of Natural Rubber is-

1. Ethylene
2. Isoprene
3. Acetylene
4. Hexane

Option “2” is correct.
Polymerization is the process of joining together a large number of small molecules to make a number of the very large molecule. Natural rubber is the natural polymer of Isoprene.
480. The predominant organic acid in grapes is-

1. Formic acid
2. Benzoic acid
3. Lactic acid
4. Tartaric acid

Option “4” is correct.
Tartaric acid is the predominant organic acid in grapes.