The magnitude of the change in oxidising power of the $M n O_{4}^{-} / M n^{2 +}$ couple is $x \times 10^{- 4} V,$ if the $H^{+}$ concentration is decreased from $1 M$ to $10^{- 4} M$ $25^{o} C$ . (Assume concentration of $M n O_{4}^{-}$ and $M n^{2 +}$ to be same on change in $H^{+}$ concentration ) . The value of $x$ is: (Rounded off to the nearest integer)
$[Given; \frac{2.303 R T}{F} = 0.059]$

3776

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3776.0

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3776.00

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Solution

$M n O_{4}^{-} + 8 H^{+} + 5 e \to M n^{2 +} + 4 H_{2} O$

$E_{M n O_{4}^{-} / M n^{2 +}} = E_{M n O_{4}^{-} / M n^{2 +}}^{o} - \frac{0.059}{5} log \frac{[M n^{2 +}]}{[M n O_{4}^{-}] [H^{+}]^{8}}$

If
$[H^{+}] = 1 M then E_{M n O_{4}^{-} / M n^{2 +}} = E_{M n O_{4}^{-} / M n^{2 +}}^{0}$

If
$[H^{+}] = 10^{- 4} M$

$E_{M n O_{4}^{-}} = E_{M n O_{4}^{-} / M n^{2 +}}^{0} - \frac{0.059}{5} l o g 10^{32}$

$E_{M n O_{4}^{-}} = E_{M n O_{4}^{-} / M n^{2 +}}^{0} - 0.3776$

Magnitude of change in oxidising power :
$= 3776 \times 10^{- 4}$

$x = 3776$

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Similar questions

The magnitude of the change in oxidising power of the $M n O_{4}^{-} / M n^{2 +}$ couple is $x \times 10^{- 4} V$ , if the $H^{+}$ concentration is decreased from $1 M$ to $10^{- 4} M$ at $25 ° C$ . (Assume concentration of $M n O_{4}^{-}$ and $M n^{2 +}$ to be same on change in $H^{+}$ concentration). The value of $x$ is . (Round off to the nearest integer).

[Given: $2.30 R T / F = 0.059$ ]

Q. If the

H^{+}

concentration is decreased from

1 M

10^{- 4} M

25^{o} C

for the couple

{M n O_{4}}^{-} / M n^{2 +}

, then the oxidising power of the

{M n O_{4}}^{-} / M n^{2 +}

couple decreases by :

Q. If the

H^{+}

concentration decreased from 1 M to

10^{- 4}

M at

25^{o} C

for the couple

M n O_{4}^{-} / M n^{2 +}

, then the oxidising power of the

M n O_{4}^{-} / M n^{2 +}

couple decreases by

Q. By how much would the oxidising power of the

(M n O_{4}^{-} | M n^{2 +})

couple change if the

H^{+}

ions concentration is decreased

100

times at

25^{\circ} C

By how much would the oxidizing power of the $M n O_{4}^{-} / M n^{2 +}$ couple change if the $H^{+}$ ions concentration is decreased to a hundredth of its initial value?

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MnO−4+8H++5e→Mn2++4H2O EMnO−4/Mn2+=EoMnO−4/Mn2+−0.0595log[Mn2+][MnO−4][H+]8 If [H+]=1Mthen EMnO−4/Mn2+=E0MnO−4/Mn2+ If [H+]=10−4M EMnO−4=E0MnO−4/Mn2+−0.0595log 1032 EMnO−4=E0MnO−4/Mn2+−0.3776 Magnitude of change in oxidising power : =3776×10−4 x=3776