Sodium sulphite `(Na_(2)SO_(3))` is added to meat as a preservative. The presence of `Na_(2)SO_(4)` 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 :

Options

A. temporary and due to its oxidizing nature
B. temporary and due to its reducing action
C. permanent and due to its oxidizing nature
D. permanent and due to its reducing action

Answer

B