Comment on the change in pH values of the following solutions during electrolysis.
a) Aqueous solution of $A g N O_{3}$
b) Aqueous saturated solution of $K C l$ .
C) Aqueous solution of $C u C l_{2}$

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Solution

(a) Aqueous solution of $A g N O_{3}$
${A g}^{+} + e^{-} \to A g ↓ H_{2} O \to H^{+} + {O H}^{-} 4 O H^{-} \to O_{2} ↑ + 2 H_{2} O + 4 e^{-}$
$H^{+}$ ions remains in solution. Hence, the value of pH decreases.

(b) Aqueous saturated solution of $K C l$
$H_{2} O \to H^{+} + {O H}^{-} 2 H^{+} + 2 e^{-} \to H_{2} ↑ 2 {C l}^{-} \to {C l}_{2} ↑ + 2 e$
${O H}^{-}$ ions remain in solution and hence, the pH increases.

(c) ${C u}^{2 +} + 2 e^{-} \to C u {2 C l}^{-} \to {C l}_{2} + 2 e^{-}$
Both $H^{+}$ ions and $O H^{-}$ ions remain in solution and hence, there is no change in pH.

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Similar questions

Predict the products of electrolysis in each of the following :

An aqueous solution of $A g N O_{3}$ with silver electrodes

An aqueous solution of $A g N O_{3}$ with platinum electrodes

A dilute solution of $H_{2} S O_{4}$ with platinum electrodes.

An aqueous solution of $C u C l_{2}$ with platinum electrodes.

Predict the products of electrolysis in each of the following:

(i) An aqueous solution of AgNO₃ with silver electrodes

(ii) An aqueous solution AgNO₃ with platinum electrodes

(iii) A dilute solution of H₂SO₄ with platinum electrodes

(iv) An aqueous solution of CuCl₂with platinum electrodes.

A g N O_{3}

Y

X

Y

p H

C u {S O}_{4}

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