Question

Two chemical reactions are given:
i. Sulphur dioxide combines with oxygen to form sulphur trioxide.
ii. Sodium reacts with water.
(a) Write the balanced chemical equation for any one of the above reactions.
(b) Which of the above reactions is a reversible reaction?
(c) What is the effect of pressure and temperature on this reversible reaction? Give reason.

Answer 1

(a) Reaction of sodium with water:
$2Na+2H_{2}O\to 2NaOH+H_2$
(b) The reaction between oxygen and sulphur dioxide:
$2S{O}_2+O_2\rightleftharpoons 2S{O}_3$
(c) There are 3 molecules on the reactant side and 2 molecules on the product side. So, the increase in the pressure of the system will favour the forward reaction. That means more products will be formed. As heat is released during the reaction between oxygen and sulphur dioxide, further increase in temperature will favour backward reaction. That means the product will decompose to reactants.