Option “D” is correct Smog is a type of air pollutant. It is composed of nitrogen oxides, sulphur oxides, ozone, smoke or particulates among others (less visible pollutants include carbon monoxide, CFCs and radioactive sources).
296. Highest percentage of carbon is found in which form of coal?
1. Anthracite
2. Bituminous
3. Peat
4. Lignite
Option “A” is correct Anthracite is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content (>90%), the fewest impurities, and the highest energy density of all types of coal except for graphite.
297. Bee sting contains ___________
1. An acidic liquid
2. A salt solution
3. An alkaline liquid
4. A corrosive liquid
Option “A” is correct Bee stings contains an acidic solution. Bee venom contains formic acid (also known as methanoic acid).
298. Radioactive disintegration of uranium ultimately results in formation of –
1. Radium
2. Thorium
3. Polonium
4. Lead
Option “D” is correct Radioactive disintegration of uranium ultimately results in the formation of lead.
299. Which of the following metals has least melting point?
1. Gold
2. Silver
3. Mercury
4. Copper
Option “C” is correct Melting point of different metals are- Copper 1083°C, Gold 1063 °C, Silver 951 °C and Mercury –38.83°C.
300. In an acid base reaction which product is produced along with a salt?
1. Hydrogen gas
2. Oxygen gas
3. Carbon dioxide
4. Water
Option “D” is correct In an acid base reaction water is produced along with salt.
