question_answer

Marshall's acid \[({{H}_{2}}{{S}_{2}}{{O}_{8}})\] or peroxo disulphuric acid is prepared by the electrolytic oxidation \[{{H}_{2}}S{{O}_{4}}\] as: \[2{{H}_{2}}S{{O}_{4}}\xrightarrow{{}}{{H}_{2}}{{S}_{2}}{{O}_{8}}+2{{H}^{\oplus }}+2{{e}^{\bigcirc -}}\] \[{{O}_{2}}(g)\] and \[{{H}_{2}}(g)\] are obtained as byproducts. In such electrolysis \[4.48\text{ }L\]of \[{{H}_{2}}(g)\] and \[1.12\text{ }L\]or \[{{O}_{2}}(g)\] were produced at STP. The weight of \[{{H}_{2}}{{S}_{2}}{{O}_{8}}\] formed is

Answer:

19.4