Sulfurous smog is formed throughans.Free radical mechanismCovalent processNone of theseIonic reaction Previous Marked for Review Next

Sulfurous smog is formed through a free radical mechanism. Here's a step-by-step explanation:

1. Sulfurous smog, also known as "London smog," is a type of air pollution that's primarily composed of sulfur dioxide (SO2) and particulates, often in the form of soot.

2. The sulfur dioxide is usually produced by burning fossil fuels, such as coal, that contain sulfur. When these fuels are burned, the sulfur in them reacts with oxygen in the air to form sulfur dioxide.

3. Once the sulfur dioxide is in the air, it can react with more oxygen to form sulfur trioxide (SO3). This reaction is catalyzed by particles in the air and is a free radical mechanism. A free radical is a molecule that has an unpaired electron, making it highly reactive.

4. The sulfur trioxide can then react with water vapor in the air to form sulfuric acid (H2SO4). This sulfuric acid can condense with other particles in the air to form the smog.

So, the formation of sulfurous smog is a complex process that involves several steps and is driven by free radical reactions.