Photochemical smog consists of an excessive amount of $X$ in addition to aldehydes,ketones,$PAN$,etc. $X$ is:

How is ozone gas produced in the stratosphere?

Chlorine atoms act as catalysts in the depletion of the ozone layer in the Earth's atmosphere. These chlorine atoms originate from which of the following?

Which of the following is not a greenhouse gas $(GHG)$?

Petroleum is a source of energy that is:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A):$ Photochemical smog causes cracking of rubber.
Reason $(R):$ Presence of ozone,nitric oxide,acrolein,formaldehyde and peroxyacetyl nitrate in photochemical smog makes it oxidizing.
Choose the most appropriate answer from the options given below: