Balance the equation in aqueous basic solution:
ClO3-(aq) + Fe(OH)3(s) → FeO42-(aq) + Cl-(aq)
See the comments on the next question above. But before you start make sure you have the correct equation. This cannot be correct as you have H atoms on the LHS and none on the RHS.
To balance the given equation in aqueous basic solution, follow the steps below:
Step 1: Write down the unbalanced equation.
ClO3-(aq) + Fe(OH)3(s) → FeO42-(aq) + Cl-(aq)
Step 2: Separate the reaction into half-reactions: one for the oxidation process and one for the reduction process.
Oxidation half-reaction: ClO3-(aq) → Cl-(aq) [Balancing Cl atoms: add 3 Cl- ions]
Reduction half-reaction: Fe(OH)3(s) → FeO42-(aq) [Balancing Fe atoms: add 3 Fe(OH)3]
Step 3: Balance the number of O atoms in both half-reactions.
In the oxidation half-reaction, there are 3 O atoms on the left side, while there are none on the right side.
Multiply the reduction half-reaction by 3 to balance the O atoms:
3 Fe(OH)3(s) → 3 FeO42-(aq)
The balanced reduction half-reaction is now:
3 Fe(OH)3(s) → 3 FeO42-(aq)
Step 4: Balance the H atoms in both half-reactions.
In the reduction half-reaction, there are 3 H atoms on the left side, while there are none on the right side.
To balance them, add 6 OH- ions on the left side of the reduction half-reaction.
3 Fe(OH)3(s) + 6 OH-(aq) → 3 FeO42-(aq)
Step 5: Balance the charges in both half-reactions.
In the oxidation half-reaction, the overall charge is -1 on both sides.
In the reduction half-reaction, the overall charge is +6 on both sides.
To balance the charges, add 6 e- to the left side of the oxidation half-reaction.
ClO3-(aq) + 6 e- → Cl-(aq)
Step 6: Combine the two half-reactions and cancel out the common species.
Multiply the oxidation half-reaction by 3 and the reduction half-reaction by 2 to balance the number of electrons.
3 ClO3-(aq) + 18 e- → 3 Cl-(aq)
2 Fe(OH)3(s) + 6 OH-(aq) → 2 FeO42-(aq)
Now, add the resulting half-reactions together, and cancel out the common species (electrons and hydroxide ions).
3 ClO3-(aq) + 2 Fe(OH)3(s) + 6 OH-(aq) → 2 FeO42-(aq) + 3 Cl-(aq) + 3 H2O(l)
Step 7: Check that all atoms and charges are balanced.
The equation is now balanced!
Thus, the balanced equation in aqueous basic solution is:
3 ClO3-(aq) + 2 Fe(OH)3(s) + 6 OH-(aq) → 2 FeO42-(aq) + 3 Cl-(aq) + 3 H2O(l)