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Electrode Potential

The standard ...

Question

The standard reduction potentials at 298 K for the following half-cell reactions are given:
$Z n^{2 +} (a q) + 2 e^{-} ⇌ Z n (s);$ $- 0.762 V$
$C r^{3 +} (a q) + 3 e^{-} ⇌ C r (s);$ $- 0.74 V$
$2 H^{+} (a q) + 2 e^{-} ⇌ H_{2} (g);$ $+ 0.00 V$
$F e^{3 +} (a q) + e^{-} ⇌ F e^{2 +} (a q);$ $+ 0.77 V$
Which one of the following is the strongest reducing agent?

Z n (s)

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C r (s)

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H_{2} (s)

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F e^{2 +} (a q)

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Solution

The correct option is A $Z n (s)$
The electrode having higher oxidation potential will be stronger reducing agent than electrode having a lower oxidation potential. Hence electrode having higher oxidation potential always undergoes oxidation during the reaction.

The electrode having lowest reduction potential will be the strongest reducing agent than electrode having lower reduction potential. Hence electrode having higher reduction potential always undergoes reduction during the reaction.
So from the given options the reaction:
$Z n^{2 +} (a q) + 2 e^{-} ⇌ Z n (s); - 0.762$
$Z n (s)$ is the strongest reducing agent.
Option A is correct.

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Similar questions

298 K

Z n^{2 +} (a q) + 2 e ⇌ Z n (s); - 0.762 V

C r^{3 +} (a q) + 3 e ⇌ C r (s); - 0.740 V

2 H^{+} (a q) + 2 e ⇌ H_{2} (g); 0.00 V

F e^{3 +} (a q) + e ⇌ F e^{2 +} (a q); 0.770 V

Z n^{2 +} (a q) + 2 e^{-} ⇌ Z n (s); E^{o} = - 0.762 V

C r^{3 +} (a q) + 3 e^{-} ⇌ C r (s); E^{o} = + 0.762 V

2 H^{+} (a q) + 2 e^{-} ⇌ H_{2} (g); E^{o} = + 0.00 V

F e^{3 +} (a q) + e^{-} ⇌ F e^{2 +} (a q); E^{o} = + 0.770 V

Z n^{2 +} (a q) + 2 e^{-} ⇌ Z n (s); - 0.762

C r^{3 +} (a q) + 3 e^{-} ⇌ C r (s); - 0.740

2 H^{⨁} (a q) + 2 e^{-} ⇌ H_{2} (g); 0.000

F e^{3 +} (a q) + 3 e^{-} ⇌ F e^{2 +} (a q); 0.770

298 K

{Z n}^{2 +} (a q) + 2 e^{-} ⇌ Z n (s) - 0.762

{C r}^{3 +} (a q) + 3 e^{-} ⇌ C r (s) - 0.74

2 H^{+} (a q) + 2 e^{-} ⇌ H_{2} (g) + 0.00

{F e}^{3 +} (a q) + e^{-} ⇌ {F e}^{2 +} (a q) + 0.77

Z n^{2 +} (a q) + 2 e ⇌ Z n (s) - 0.762

C r^{3 +} (a q) + 2 e ⇌ C r (s) - 0.740

2 H^{+} (a q) + 2 e ⇌ H_{2} (g) 0.000

F e^{3 +} (a q) + 2 e ⇌ F e^{2 +} (a q) 0.770

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