Question
Which of the following is laboratory preparation of dihydrogen?
A.
$$3Fe + 4{H_2}O\left( {{\text{steam}}} \right) \to F{e_3}{O_4} + 4{H_2}$$
B.
$$2Na + 2{H_2}O \to 2NaOH + {H_2}$$
C.
$$Ca{H_2} + 2{H_2}O \to Ca{\left( {OH} \right)_2} + 2{H_2}$$
D.
$$Zn + {H_2}S{O_4}\left( {{\text{dil}}{\text{.}}} \right) \to ZnS{O_4} + {H_2}$$
Answer :
$$Zn + {H_2}S{O_4}\left( {{\text{dil}}{\text{.}}} \right) \to ZnS{O_4} + {H_2}$$
Solution :
In laboratory, hydrogen gas is prepared by action of dilute $${H_2}S{O_4}$$ on granulated zinc.
$$Zn + {H_2}S{O_4}\left( {{\text{dil}}{\text{.}}} \right) \to ZnS{O_4} + {H_2}$$