Consider the following equilibrium reaction having gaseous reactants and products.

4HCl + O2 ⇌ 2H2O + Cl2

Which of the following would result from increasing the volume of oxygen?

A. The volume of hydrochloric acid increases.

B. The rate of forward reaction increases.

C. The rate of backward reaction increases.

D. The volume of water vapor decreases.

Answer;

B. The rate of forward reaction increases.

Explanation; Le Chatelier's principle states that changing a factor such as concentration, temperature, or pressure of a reaction at equilibrium will cause the reaction to shift in the direction that counteracts the effect of that change. Therefore, when reactants are added to a reaction at equilibrium shift when more reactants are added then the reaction shifts to the right to make more products.