Question

For a particular redox reaction BrO– is oxidized to BrO3– and Fe3 is reduced to Fe2 . Complete and balance the equation for this reaction in basic solution. Phases are optional.

Answer 1

NaBrO + 2Fe₂(SO₄)₃ + 12NaOH = NaBrO₃ + 4Fe(OH)₂ + 6Na₂SO₄ + 2H₂O

BrO⁻ + 4OH⁻ - 4e⁻ = BrO₃⁻ + 2H₂O k=1
Fe³⁺ + 2OH⁻ + 1e⁻ = Fe(OH)₂ k=4

BrO⁻ + 12OH⁻ + 4Fe³⁺ = BrO₃⁻ + 2H₂O + 4Fe(OH)₂

Answer 2

Answer : The balanced chemical equation in a basic solution will be,

`BrO^-+4OH^-+4Fe^(3+)\rightarrow BrO_3^-+2H_2O+4Fe^(2+)`

Explanation :

Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.

Rules for the balanced chemical equation in basic solution are :

• First we have to write into the two half-reactions.
• Now balance the main atoms in the reaction.
• Now balance the hydrogen and oxygen atoms on both the sides of the reaction.
• If the oxygen atoms are not balanced on both the sides then adding water molecules at that side where the more number of oxygen are present.
• If the hydrogen atoms are not balanced on both the sides then adding hydroxide ion
  `(OH^-)` at that side where the less number of hydrogen are present.
• Now balance the charge.

The oxidation-reduction half reaction will be :

Oxidation :
`BrO^-+4OH^-\rightarrow BrO_3^-+2H_2O+4e^-`

Reduction :
`Fe^(3+)+1e^-\rightarrow Fe^(2+)`

In order to balance the electrons, we multiply the reduction reaction by 4 and then added both equation, we get the balanced redox reaction.

The balanced chemical equation in a basic solution will be,

`BrO^-+4OH^-+4Fe^(3+)\rightarrow BrO_3^-+2H_2O+4Fe^(2+)`