In the following schematic diagram for the preparation of hydrogen gas, as shown in Figure 2.3, what would happen if the following changes are made?

(a) In place of zinc granules

(a) If in the place of zinc granules, the same amount of zinc dust is taken in the test tube then the rate of the reaction will increase and the reaction will take place faster. The surface area per unit volume of powder is more than that of the zinc granules and hence the powder will provide more surface area for the reaction to take place.

(b) If in place of dilute sulphuric acid, we use dilute hydrochloric acid then no change in the reaction will be observed because both are strong acids.

(c) With copper turnings, hydrogen gas will not evolve because copper is less reactive, so, it does no react with dil. $H_{2}SO_{4}$ or dil. HCl. Hence, no reaction will take place.

(d) If sodium hydroxide is taken in place of dilute sulphuric acid and the test tube is heated then the metal will react with the base to form the corresponding salt and will evolve hydrogen gas. The reaction is given below: