Question

Match the chemicals with the impurities they remove during the purification of impure $H_2$ gas.

• A. $H_{2}S$
• B. $P{H}_3$
• C. $C{O}_2$

Answer 1

The impure hydrogen gas is passed through various solutions to remove impurities such as phosphine, hydrogen sulphide, carbon dioxide, water vapour, sulphur dioxide, etc.

1. $AgN{O}_3$ combines with $P{H}_3$ present in the impure $H_2$ gas and converts it into $A{g}_{3}P$.
$3AgN{O}_3+P{H}_3\to A{g}_{3}P+3HN{O}_3$

2. $Pb(N{O}_3{)}_2$ combines with $H_{2}S$ and converts it into $PbS$.
$Pb(N{O}_3{)}_2+H_{2}S\to PbS+2HN{O}_3$

3. $KOH$ combines with $C{O}_2$ and converts it into $K_{2}C{O}_3$.
$2KOH+C{O}_2\to K_{2}C{O}_3+H_{2}O$