Locking of chlorine monoxide and free radicals of chlorine is called SCAVENGING. In the atmosphere, nitrogen dioxide scavenges chlorine monoxide and methane scavenges chlorine atoms, which are responsible for:

P — Acid rain

Q — Global warming

R — Ozone depletion

1. Only P
2. Only Q
3. Only R
4. Both P and Q

pH of acid rain usually ranges between:

P — 7.5 to 9.7

Q — 2 to 5

R — 3.5 to 5.6

1. Only P
2. Only Q
3. Only R
4. Both Q and R

Assertion (A): Excessive burning of fossil fuels and the use of automobiles do not cause air pollution.

Reason (R): Incomplete combustion of fuels which leads to the formation of CO is a cause of air pollution.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): The formation of ozone involves a chemical reaction called photolysis.

Reason (R): The highly energetic ultraviolet radiation from the sun breaks the oxygen molecules into oxygen atoms. Oxygen atoms then react with oxygen molecules to form ozone.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.