Question
Why are pure zinc and concentrated sulphuric acid not used in the preparation of hydrogen?
Solution
(i) Completely pure zinc metal is not used for the preparation of hydrogen because it is slowly attacked by the acid. The presence of impurities increases the rate of the reaction by forming electrochemical couples.
(ii) Concentrated H2SO4 cannot be used for the preparation of hydrogen gas as it results in the formation of SO2 gas instead of H2 from zinc.
