Question

In acid rain, sulphuric acid accounts for

• A. 100% of acid
• B. 70% of acid
• C. 50% of acid
• D. 30% of acid

Answer 1

The correct option is B 70% of acid

Acid rain is acidic with a pH of below 5.6. Rain becomes acidic because of gases that dissolve in the rain. Approximately 70% of acid rain is a result of dissolved sulfur dioxide ($S{O}_2$), which forms sulphuric acid. The remaining 30% or so comes from various nitrogen oxides (mostly $N{O}_2$ and $N{O}_3$, which has collectedly called NOx). There are also a small percentage of hydrochloric acid and carbonic acid.

The equation is as follows:

Sulphuric acid when it joins with hydrogen atoms in the air:

$S{O}_3$(g) + $H_{2}O$ (l) = $H_{2}S{O}_4$ (aq).

In the air, the nitrogen ion becomes nitric or nitrous acid:

$N{O}_2$(g) + $H_{2}O$(l) = $HN{O}_3$ (aq) + $HN{O}_2$(aq).