Sodium sulphite `(Na_(2)SO_(3))` is added to meat as a preservative. The presence of `Na_(2)SO_(3)
Channel: Doubtnut
Date: 2020-05-31

Sodium sulphite `(Na_(2)SO_(3))` is added to meat as a preservative. The presence of `Na_(2)SO_(3)` can be detected by adding dil. `H_(2)SO_(4)` when the pungent smelling gas evolved turns the lime water milky. The gas evolved was detected as sulphur dioxide. The `SO_(2) " to "SO_(4)^(2-)` in titration.  `SO_(2)+2H_(2)O+I_(2) to 4H^(+)+SO_(4)^(2-)+2I^(-)`  In order to check the results of titration, excess barium chloride is added to the final solution. The resulting precipitate is collected and weighed.  Q.  `SO_(2)` gas is used as bleaching agent. Its bleaching action is :