Write the balanced chemical equations for the following reactions.
a. An aqueous solution solution of sodium nitrite is heated with zinc dust and caustic soda solution.
b. Sodium iodate is added to a solution of sodium bisulphite.

Explanation

a. Ammonia is produced.
`3Zn+NaNO_(2)+5NaOH rarr 3Na_(2)ZnO_(2)+NH_(3)+H_(2)O`
b. `4overset(Θ)OH+2H_(2)O+underset(x=0)(Zn) rarr underset(X-4= -2)(ZnO_(2)^(2-))+4H_(2)O+2e^(-)]xx3`
`7H_(2)O+6e^(-)+underset(x=3)underset(x-4= -1)(NO_(2)^(Θ))rarr underset(x= -3)underset(x+3=0)(NH_(3))+2H_(2)O+OH`
`5NaOH+NO_(2)^(Θ)+3Zn rarr 3ZnO_(2)^(2-)+NH_(3)+H_(2)O`
(Add `6Na^(o+)` ions on both sides)
`ulbar(5NaOH+NaNO_(2)+3Zn rarr 3Na_(2)ZnO_(2)+H_(2)O+NH_(3))`