Statement-1: When ${\mathrm{H}}_2\mathrm{S}$ gas is passed through N a-nitroprusside solution it gives Purple colouration. 

Statement-2: ${\mathrm{H}}_2\mathrm{S}$ is a weak acid.

Statement-1 is False, Statement-2 is True.

We know that, two base molecules will be neutralized by hydrogen sulfide. Hydrogen sulfide is a dibasic acid because it may give two protons to neutralize two base molecules. Hydrogen sulfide has a relatively low acid dissociation constant, which makes it a weak acid. Hence, option D is correct.