When sodium and zinc were made to react individually with dilute hydrochloric acid then the reaction was much faster in the case of sodium. Which of the following factor had an influence on the rate of the reaction?

The correct option is B The nature of the reactant

There are several factors which affect the rate of the reaction. These factors are:

(i) The concentration of the reactant- The rate of the reaction increases with the increase in the concentration. Here, sodium and zinc are of the same concentration so concentration is not the factor which is affecting the rate of the reaction.

(ii) The pressure of the gases- The rate of the reaction increases if the pressure on the reacting gases is increased. Here, sodium and zinc metal are not in gaseous form, so, pressure will not have any influence on the rate of the reaction.

(iii) The surface area of the solids- The rate of the reaction increases if the exposed surface area of the reactants is more. Since, the exposed surface area of zinc and sodium is the same, so, surface area is not the factor which has influence on the rate of the reaction.

(iv) The nature of the reactant- The factor which is affecting the rate of the reaction here is the nature of the reactant as sodium is more reactive than zinc and hence the speed of reaction is faster in the case of sodium.