Question

In the laboratory prepration of hydrogen, pure zinc is not used because:

• A. pure zinc becomes passive due to formation of oxide layer
• B. pure zinc becomes passive due to the formation of sulphate layer over the metal
• C. pure zinc reacts slowly with the acid
• D. pure zinc reacts with acid vigorously and violently

Answer 1

Answer: (C)

pure zinc reacts slowly with the acid

Pure zinc is not used in laboratory preparation of hydrogen because it is non-porous in nature. As a result reaction would occur very slowly. Hence impurities like copper is added to the zinc which increases the speed of the reaction.