Question

balance redox reaction that occurs in acidic conditions. what are coefficients for H + & Fe3+ once reaction is balanced? write it as H+=#; Fe +3 = #

Fe2+(aq)+Mn04-(aq) -> Fe3+(aq)+Mn2+(aq)

Answer 1

Unbalanced equation: Fe2++MnO4-→Fe3++Mn2+

Steps for balancinf the reaction:

1. Oxidation numbers of every atom are identified.

L.H.S: Fe=+2 ; Mn=+7 ; O=-2

R.H.S: Fe=+3 ; Mn=+2

2. Determine The change in oxidation number for each atom that changes are determined.

Fe: +2 → +1; Change = +1
Mn: +7 → +2; Change = -5

3. Total increase in oxidation number is made equal to the total decrease in oxidation number.

5 atoms of Fe are needed for every 1 atom of Mn. Total changes of +5 and -5.

4. These numbers are placed as coefficients in front of the formulas containing those atoms.

5Fe2++1MnO4-→5Fe3++1Mn2+

5. All remaining atoms are balanced other than H and O

6. Balance O.

Enough H2O molecules are added to the deficient side to balance O.

We have 4 O atoms on the left, so we need 4 H2O on the right.

5Fe2++1MnO4-→5Fe3++1Mn2++4H2O

7. Balance H.

Enough H+ ions are added to the deficient side to balance H.

We have 8 H atoms on the right, so we need 8 H+ on the left.

5Fe2++1MnO4-+8H+→5Fe3++1Mn2++4H2O

8. Atoms and charges balance are checked for both sides.

On the left: : 5 Fe; 1 Mn; 8 H; 4 O
On the right: 5 Fe; 1 Mn; 8H; 4 O

On the left: +10- 1 + 8 = +17
On the right: +15 + 2=+17

The balanced equation is

5Fe2++MnO4-+8H+→5Fe3++Mn2++4H2O

The answer is H+=8; Fe3+ = 5