Name: Redox Reactions as a Basis for Titration
Uploaded: 2019-07-19
Duration: 7 min 17 s
Description: This video will help us learn about how redox indicators like potassium permanganate or diphenylamine are used to indicate the completion of a redox reaction...

Question

Balance the following equations in acidic medium by both oxidation number and ion electron methods and identify the oxidants and the reductants:

{MnO}_{4}^{-} (aq) + {Fe}^{2 +} (aq) \to {Mn}^{2 +} (aq) + {Fe}^{3 +} (aq)

Accepted Answer

Oxidation no. method:
Step 1:
The given ionic equation is:
${MnO}_{4}^{-} (aq) + {Fe}^{2 +} (aq) \to {Mn}^{2 +} (aq) + {Fe}^{3 +} (aq)$
Step 2:
We assign oxidation nos. and balance the increase and decrease
$\overset{+ 7}{Mn} O_{4}^{-} (aq) + 5 {Fe}^{2 +} (aq) \to {Mn}^{2 +} (aq) + 5 {Fe}^{3 +} (aq)$

We balance the charges by adding $H^{+}$ , balance the hydrogens by adding water molecules,
$\overset{+ 7}{Mn} O_{4}^{-} (aq) + 5 {Fe}^{2 +} (aq) + 8 H^{+} (aq) \to {Mn}^{2 +} (aq) + 5 {Fe}^{3 +} (aq) + 4 H_{2} O (l)$

Ion-Electron method:
Step 1:
We divide both the equations into oxidation and reduction half reactions:
$(O) : {Fe}^{2 +} (aq) \to {Fe}^{3 +} (aq) (R) : {MnO}_{4}^{-} (aq) \to {Mn}^{2 +} (aq)$
Step 2:
We balance oxygen by adding water molecules and balance hydrogen by adding $H^{+}$ :
$(O) : {Fe}^{2 +} (aq) \to {Fe}^{3 +} (aq) (R) : {MnO}_{4}^{-} (aq) + 8 H^{+} (aq) \to {Mn}^{2 +} (aq) + 4 H_{2} O (l)$

We balance charges by adding electrons and then manipulate both the equations to eliminate them:
$(O) : ({Fe}^{2 +} (aq) \to {Fe}^{3 +} (aq) + e^{-}) \times 5 (R) : {MnO}_{4}^{-} (aq) + 8 H^{+} (aq) + 5 e^{-} \to {Mn}^{2 +} (aq) + 4 H_{2} O (l)_________________________________________________5 {Fe}^{2 +} (aq) + {MnO}_{4}^{-} (aq) + 8 H^{+} (aq) \to 5 {Fe}^{3 +} (aq) + {Mn}^{2 +} (aq) + 4 H_{2} O (l)$

Balance the following equations in acidic medium by both oxidation number and ion electron methods and identify the oxidants and the reductants:
${MnO}_{4}^{-} (aq) + {Fe}^{2 +} (aq) \to {Mn}^{2 +} (aq) + {Fe}^{3 +} (aq)$

Important Questions on Redox Reactions

Learn and Prepare for any exam you want !

Balance the following equations in acidic medium by both oxidation number and ion electron methods and identify the oxidants and the reductants: MnO4–aq+Fe2+aq→Mn2+aq+Fe3+aq

Important Questions on Redox Reactions

Learn and Prepare for any exam you want !

Balance the following equations in acidic medium by both oxidation number and ion electron methods and identify the oxidants and the reductants:
${MnO}_{4}^{-} (aq) + {Fe}^{2 +} (aq) \to {Mn}^{2 +} (aq) + {Fe}^{3 +} (aq)$