Question

Which of the following is not true about the preparation of hydrogen gas?

• A. Hydrogen is produced by the action of acids on metals.
• B. Aluminum reacts with steam to produce aluminum oxide and hydrogen gas
• C. Hydrogen is produced by the action of mineral acids on silver.
• D. Hydrogen is produced by the action of mineral acids on gold.

Answer 1

Answer: (C), (D)

The correct options are
C Hydrogen is produced by the action of mineral acids on silver.
D Hydrogen is produced by the action of mineral acids on gold.

Hydrogen is produced by the action of acids on metals.
$Mg+2HCl\to MgC{l}_2+H_2$
When aluminum reacts with steam, it produces aluminum oxide and hydrogen gas.
$2Al+3H_{2}O\to A{l}_2{O}_3+3H_2$

Metals which lie above hydrogen in activity series displace hydrogen gas from mineral acids. Since silver and gold are below hydrogen in the activity series, mineral acids do not react with silver and gold to produce hydrogen gas.