In the following diagram for preparation of hydrogen gas as shown in the figure, what would happen if the following changes are made? (a) in place of zinc granules, same amount of zinc dust is taken in the test tube.(b) instead of dilute sulphuric acid, dilute hydrochloric acid is taken(c) sodium hydroxide is taken in place of dilute sulphuric acid and the tube is heated.

if you use Zin dust it has more reactivity towards the H2SO4 than the Zn Granule and the rate of baubles formation will increase

addition of NaOH will produce H2 but the rate is very low due to less reactivity of Zn toward the NaOH

and Dilute HNO3 also produces the H2 gas spontaneous than the H2SO4

for all these you should know the electrochemcial potential and H2 evolution potential in electrochemcial seris.