Chapter 7, Problem 92E

A main source of soulful oxide pollutants are smelters where sulfide ores are converted into metals. The first step in this the process is the reaction of the sulfide ore with oxygen in reactions such as:

a. $2\text{ PbS(}s{\text{)+3 O}}_{\text{2}}(g)\underset{\text{UV light}}{\to }2\text{ PbO(}s\text{)}+2{\text{ SO}}_{\text{2}}\left(g\right)$

Sulfur dioxide can then react with oxygen in air to from sulfur trioxide.

b. $2{\text{ So}}_{\text{2}}\left(g\right)+{\text{O}}_{\text{2}}\left(g\right)\to 2{\text{ SO}}_3\left(g\right)$

Sulfur trioxide can then react with water from rain to from sulfuric acid that falls as acid rain:

${\text{So}}_3\left(g\right)+{\text{H}}_{\text{2}}\text{O }\left(l\right)\to {\text{ H}}_{\text{2}}{\text{SO}}_4\left(ag\right)$

Classify each of the preceding reactions (a, b, c) as a synthesis, decomposition, single-displacement, or double-displacement reaction.