Balance the following equation by oxidation number method-Fe2- - Cr2O72- - H- - Fe3- - Cr3- - H2O

Equation Fe2+ + Cr2O72 + H+ nbsp; #8594; nbsp;Fe3+ + Cr3+ + H2O The oxidation number of chromium decreases from +6 in Cr2O72 nbsp; nbsp;to +3 in Cr3 ...

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Standard IX

Chemistry

Double Displacement Reaction

Balance the f...

Question

Balance the following equation by oxidation number method-
Fe²⁺ + Cr₂O₇^2- + H⁺ ---- Fe³⁺ + Cr^3- + H₂O

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Solution

Equation-
Fe²⁺ + Cr₂O₇²^- + H⁺ $\to$ Fe³⁺ + Cr³⁺ + H₂O
The oxidation number of chromium decreases from +6 in Cr₂O₇² to +3 in Cr³⁺. The total decrease for two chromium atoms in Cr₂O₇²^- to Cr³⁺ is 6. On the other hand, the oxidation number of iron increases from +2 (in Fe²⁺) to +3 (in Fe³⁺).

To balance increase and decrease of oxidation numbers, multiply Fe²⁺ by 6 and Cr₂O₇²^- by 1. Then we get,
6Fe²⁺ + Cr₂O₇²^- + H⁺ $\to$ Fe³⁺ + Cr³⁺ + H₂O

Balancing Fe and Cr atoms on both side of reaction.
6Fe²⁺ + Cr₂O₇²^- + H⁺ $\to$ 6Fe³⁺ + 2Cr³⁺ + H₂O

To balance O atoms multiply H₂O by 7
6Fe²⁺ + Cr₂O₇²^- + H⁺ $\to$ 6Fe³⁺ + 2Cr³⁺ + 7H₂O

To balance H-atoms multiply H⁺ by 14
6Fe²⁺ + Cr₂O₇²^- + 14H⁺ $\to$ 6Fe³⁺ + 2Cr³⁺ + 7H₂O

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Similar questions

Q. Balance the following equations by oxidation number method.

{C r_{2} O_{7}}^{2 -} + H N O_{2} + H^{+} \to C r^{3 +} + {N O_{3}}^{-} + H_{2} O

Q. Balance the following ionic equations
(i)

C r_{2} O_{7}^{2 -} + H^{+} + I^{-} \to C r^{3 +} + I_{2} + H_{2} O

(ii)

C r_{2} O_{7}^{2 -} + F e_{2}^{+} + H^{+} \to C r^{3 +} + F e^{3 +} + H_{2} O

(iii)

M n O^{4 -} + S O_{3}^{2 -} + H^{+} \to M n^{2 +} + S O_{4}^{2 -} + H_{2} O

(iv)

M n O^{4 -} + H^{+} + B r^{-} \to M n^{2 +} + B r_{2} + H_{2} O

C r_{2} O_{7}^{2 -} + F e^{2 +} + H^{+} \to C r^{3 +} + F e^{3 +} + H_{2} O

Complete the reaction.

Q. Balance the following equation by ion electron method.

{C r_{2} O_{7}}^{2 -} + H^{+} + {C_{2} O_{4}}^{2 -} \to C r^{3 +} + C O_{2} + H_{2} O

Q. Balance the following equations by ion electron method:

{C r_{2} O_{7}}^{2 +} + S O_{2} + H^{+} \to C r^{3 +} + {H S O_{4}}^{-} + H_{2} O

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Balance the following equation by oxidation number method-Fe2+ + Cr2O72- + H+ ---- Fe3+ + Cr3- + H2O

Balance the following equation by oxidation number method-
Fe²⁺ + Cr₂O₇^2- + H⁺ ---- Fe³⁺ + Cr^3- + H₂O