Question

Identify the gas evolved and give the chemical test when dilute hydrochloric acid reacts with sodium sulfide?

Answer 1

1. In these reaction sulfur di-oxide gas is evolved.
2. It is a colourless gas with smell of burning sulfur.
3. In the test it turns acidified sodium di-chromate orange to green.

$$\begin{gathered} {\mathrm{Na}}_2{\mathrm{SO}}_3+\mathrm{HCl}\to \mathrm{NaCl}+{\mathrm{SO}}_2+{\mathrm{H}}_2\mathrm{O} \\ (\mathrm{sodium}(\mathrm{Dil}.\mathrm{hydrochloric}(\mathrm{sodium}(\mathrm{sulfur}\left(\mathrm{water}\right) \\ \mathrm{sulfide})\mathrm{acid})\mathrm{cloride})\mathrm{di}-\mathrm{oxide}) \end{gathered}$$