Question

For a particular redox reaction BrO– is oxidized to BrO3– and Ag is reduced to Ag. Complete and balance the equation for this reaction in basic solution. Phases are optional.

Answer 1

The oxidation reaction is : BrO^- BrO₃^-       (Since the oxidation state of Br increases from +1 to +5 )

Balance O atoms(by adding H₂O molecules in the deficient side) : BrO^- +2H₂O BrO₃^-   

Balance H atoms ( adding H₂O on the deficient side& added the same number of OH^- on the other hand)

                                                     : BrO^- +2H₂O + 4OH^- BrO₃^- + 4H₂O

Balance charge( by adding e^-)    : BrO^- +2H₂O + 4OH^- BrO₃^- + 4H₂O +4e^- ---------------(1)

The reduction reaction is : Ag⁺   Ag

Balance charge( by adding e^-)   : Ag⁺ + e^-   Ag                                           --------(2)

The net equation is obtained by combining (1) & (2) so that charge must be balanced,This must be done as follows:

   Eqn(1) + 4x Eqn(2) gives

BrO^- +2H₂O + 4OH^- + 4Ag⁺ + 4e^-    BrO₃^- + 4H₂O +4e^- + 4Ag

BrO^- + 4OH^- + 4Ag⁺   BrO₃^- + 2H₂O + 4Ag

This is the balanced Equation in basic medium.