Question:

Which one of the following statements is false?

London smog is a mixture of smoke and fog

Photochemical smog causes irritation in eyes

London smog is oxidising in nature

Photochemical smog results in the formation of PAN

Solution:

Reducing smog is known as the London smog. Smog is a mixture of smoke and fog and they cause irritation in eyes. London smog, also known as reducing smog, is mainly composed of sulfur dioxide and particulate matter, making it reducing in nature, not oxidizing. Therefore, the statement 'London smog is oxidizing in nature' is false.