Question

Which of these can cause acid rain?
(a) carbon monoxide
(b) carbon dioxide
(c) sulphur dioxide
(d) nitrogen

Answer 1

(c) sulphur dioxide

Sulphur dioxide causes acid rain by reacting with oxygen present in the atmosphere and then combining with rain water.

${\mathrm{SO}}_2\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to \mathrm{S}{\mathrm{O}}_3(g)$
${\mathrm{SO}}_3\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O(l)}\to {\mathrm{H}}_2{\mathrm{SO}}_4(l)$