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Anomalous Behaviour of Oxygen

Peroxodisulph...

Question

Peroxodisulphate salts (e.g., $N a_{2} S_{2} O_{8}$ ) are strong oxidising agents used as bleaching agents for fats, oils and fabrics. Can oxygen gas oxidise sulphate ion to peroxodisulphate ion $(S_{2} O_{8}^{2 -})$ in acidic solution, with the $O_{2} (g)$ being reduced to water? Given,
$O_{2} (g) + 4 H^{+} (a q) + 4 e \to 2 H_{2} O E^{o} = 1.23 V$
$S_{2} O_{8}^{2 -} (a q) + 2 e \to 2 S O_{4}^{2 -} (a q) E^{o} = 2.01 V$

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Solution

Since $E^{o} {R e d}^{n}$ of $O_{2}$ is less than that of $E^{o} {R e d}^{n}$ of $S_{2} O_{8}^{2 -}$ .
$∴$ Oxygen can oxidise undergo oxidation self. But oxygen will reduce $S_{2} O_{8}^{2 -}$ to ${S O}_{4}^{2 -}$ .

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Similar questions

O_{2} (g) + 4 H^{\oplus} (a q) + 4 e^{-} \to 2 H_{2} O (l)

E^{\oplus} = 1.23 V

S_{2} O_{8}^{2 -} (a q) + 2 e^{-} \to 2 S O_{2}^{4 -} (a q)

E^{⊖} = 2.01 V

(e . g ., N a_{2} S_{2} O_{8})

(S_{2} O_{8}^{2 -})

O_{2} (g)

Peroxodisulphate salts (e.g., $N a_{2} S_{2} O_{8}$ ) are strong oxidizing agents used as
bleaching agents for fats, oils, etc.

Given :

$O_{2} (g) + 4 H^{\oplus} (a q) + 4 e^{-} \to 2 H_{2} O (l)$

$E^{⊖} = 1.23 V$

$S_{2} O_{8}^{2 -} (a q) + 2 e^{-} \to S O_{4}^{2 -} (a q)$

$E^{⊖} = 2.01 V$

C u S O_{4}

(I^{-})

[S_{2} O_{8}^{2 -}]

2 I^{-} (a q) + S_{2} O_{8}^{2 -} (a q) \to I_{2} (a q) + 2 S_{2} O_{4}^{- 2} (a q) (s l o w)

I_{2} (a q) + 2 S_{2} O_{3}^{2 -} (a q) \to 2 I^{-} (a q) + S_{4} O_{6}^{2 -} (a q) (f a s t)

S_{2} O_{3}^{2 -}

(S_{2} O_{8}^{2 -})

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