Question

The oxidation of $S{O}_2$ by $O_2$ to $S{O}_3$ is an exothermic reaction. The yield of $S{O}_3$ will be maximum if

• A. temperature is increased and pressure is kept constant.
• B. temperature is reduced and pressure is increased.
• C. both temperature and pressure are increased.
• D. both temperature and pressure are reduced.

Answer 1

The correct option is B temperature is reduced and pressure is increased.

$S{O}_{2\left(g\right)}+\frac{1}{2}{O}_{2\left(g\right)}\to S{O}_{3\left(g\right)};\Delta H=$ negative
.According to Le-Chatlier principle exothermic reactions are favored at low temperature. The number of moles' are decreasing in reaction. Such reactions, according to Le Chateler principle are favoured at high' pressure.
$\therefore$ This reaction will give maximum yield at reduced temperature and high pressure.