Question

Which gas is primarily responsible for the corrosion of metals and monuments in polluted urban environments?

• A. Sulphur dioxide
• B. Carbon monoxide
• C. Methane
• D. Nitrogen

Hint:

Acid rain is mainly caused by \[ \boxed{\mathrm{SO_2}\ \text{and}\ \mathrm{NO_x}} \] leading to corrosion of metals and damage to monuments.

Answer 1

The Correct Option is A

Step 1: Track the chemistry of sulphur dioxide in the air.
Sulphur dioxide reacts with moisture and oxygen in the atmosphere to form sulphurous and sulphuric acid droplets.
Step 2: See how this reaches the ground.
These acidic droplets fall back down as acid rain, wetting buildings, metal structures and monuments.
Step 3: Connect this to corrosion.
The acid reacts with metal surfaces and with the calcium carbonate in marble and limestone, gradually corroding and eroding them.
\[ \boxed{\text{Sulphur dioxide}} \]