Identify the Oxidation and reduction half reaction in 2 KMNO4 + 10 FeSO4 + 8 H2SO4 -> K2SO4 + 2 MNSO4 + 5 Fe2(SO4)3 + 8 H2O
Write net ionic equation
Oxidation is the loss of electrons. So Fe goes from +2 on the left to +3 on the right and Mn goes from +7 on the left to +2 on the right. Which loses electrons. You try writing the equations.
If you have 30 mols KMnO4 you must have reacted it with 30 x 10/2 = ? and that sure looks like 150 to me.
To identify the oxidation and reduction half-reactions, you first need to determine the oxidation states of the elements involved in the reaction.
In the given reaction:
2 KMnO4 + 10 FeSO4 + 8 H2SO4 -> K2SO4 + 2 MnSO4 + 5 Fe2(SO4)3 + 8 H2O
Let's break down the reaction and assign oxidation states:
Oxidation state of K (potassium) is +1. It does not change in the reaction.
Oxidation state of Mn (manganese) in KMnO4 is +7 since oxygen (O) has an oxidation state of -2.
Oxidation state of Fe (iron) in FeSO4 is +2 since sulfate (SO4) has an oxidation state of -2.
Oxidation state of S (sulfur) in H2SO4 and Fe2(SO4)3 is +6 since oxygen (O) has an oxidation state of -2.
Oxidation state of H (hydrogen) in H2SO4 and H2O is +1.
Oxidation state of O (oxygen) is usually -2.
Now that we have determined the oxidation states, we can identify the oxidation and reduction half-reactions:
1. Oxidation Half-Reaction:
In the reaction, the Mn atom changes from +7 in KMnO4 to +2 in MnSO4. So, Mn undergoes a reduction in its oxidation state.
The half-reaction for the reduction of Mn is:
MnO4- -> Mn2+
Overall charge: -1 -> 0
2. Reduction Half-Reaction:
In the reaction, the Fe atom changes from +2 in FeSO4 to +3 in Fe2(SO4)3. So, Fe undergoes an oxidation in its oxidation state.
The half-reaction for the oxidation of Fe is:
Fe2+ -> Fe3+
Overall charge: 0 -> +1
Now, let's write the net ionic equation by combining the two half-reactions:
2 MnO4- + 10 Fe2+ + 8 H+ -> 2 Mn2+ + 5 Fe3+ + 4 H2O
In the net ionic equation, we eliminate the spectator ions (K+ and SO42-) that do not get oxidized or reduced in the reaction.
Suppose that an endpoint is reacted when 30 moles of KMnO4 was added. How many moles of Fe^2+ was there originally.
I thought the answer was 150 moles.