Question

When the same amount of zinc is treated separately with excess of sulphuric acid and excess of sodium hydroxide, the ratio of volumes of hydrogen evolved is: A) 1:1 B) 1:2 C) 2:1 D) 9:4

Answer 1

Answer:The balanced chemical equation for the reaction of zinc with sulfuric acid is as shown below:

Zn+H  2  SO  4 →ZnSO  4 +H  2  (g)↑

1 mole of zinc reacts with 1 mole of sulfuric acid to produce 1 mole of hydrogen.

The balanced chemical equation for the reaction of zinc with sodium hydroxide is as shown below:

Zn+2NaOH+2H 2 O→Na  2  [Zn(OH)  4 ]+H 2 (g)↑

1 mole of zinc reacts with 2 moles of sodium hydroxide to produce 1 mole of hydrogen.

Thus, the ratio of volumes of hydrogen evolved is 1:1.