question_answer

When \[{{H}_{2}}S\] gas is passed through an aqueous solution of \[S{{O}_{2}}\] gas, a yellow turbidity is formed. Why?

Answer:

                On passing \[{{H}_{2}}S\] gas through a solution of \[S{{O}_{2}}\], oxidation of\[{{H}_{2}}S\] occurs. The particles of sulphur that are formed get condensed to be in the colloidal range. Therefore, the milky solution contains colloidal particles of sulphur. \[2{{H}_{2}}S+S{{O}_{2}}\xrightarrow{\,}\,\underset{\text{(Colloidal)}}{\mathop{3S+2{{H}_{2}}O}}\,\]