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Redox Reactions and Couple

In the button...

Question

In the button cells widely used in watches and other devices the following reaction takes place:
$Z n (s) + A g_{2} O (s) + H_{2} O (l) \to Z n^{2 +} (a q) + 2 A g (s) + 2 O H^{-} (a q)$
Determine $Δ_{r} G^{θ}$ and $E^{θ}$ for the reaction.

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Solution

$E_{c e l l}^{0} = E_{c a t h o d e}^{0} - E_{a n o d e}^{0} = E_{A g}^{o} - E_{Z n}^{o} = 0.344 - (- 0.76) = 1.104$ V
$Δ G^{0} = - n F E_{c e l l}^{0} = - 2 \times 96500 \times 1.104 = - 213072 J = - 213 k J$

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Similar questions

In the button cells widely used in watches and other devices the following reaction takes place:

Zn(s) + Ag₂O(s) + H₂O(l) → Zn²⁺(aq) + 2Ag(s) + 2OH⁻(aq)

Determine and for the reaction.

Z n (s) + A g_{2} O (s) + H_{2} O (l) ⇌ 2 A g (s) + Z n^{2 +} (a q) + 2 O H^{-} (a q)

Z n^{2 +} (a q) + 2 e^{-} \to Z n (s); E^{\circ} = - 0.76 V

A g_{2} O (s) + H_{2} O (l) + 2 e^{-} \to 2 A g (s) + 2 O H^{-} (a q), E^{\circ} = 0.34 V

Z n (s) + A g_{2} O (s) + H_{2} O (l) ⇌ 2 A g (s) + Z n^{2 +} (a q) + 2 O H^{-} (a q)

Z n^{2 +} (a q) + 2 e \to Z n (s); E^{0} = - 0.76 V

A g_{2} O (s) + H_{2} O (l) 2 e \to 2 A g (s) + 2 O H^{-} (a q), E^{0} = 0.34 V

Z n (s) + A g_{2} O (s) + H_{2} O (l) \to Z N^{2 +} (a q) + 2 (A g (s) + 2 O H^{-} (a q)

E^{o}

Δ G^{o}

E_{A g^{+} / A g}^{o} = + 0.80 V, E_{Z n^{2 +} / Z n}^{o} = - 0.76 V)

△ G^{\circ}

Z n (s) + A g_{2} O (s) + H_{2} O (l) ⇌ Z n^{2 +} (a q) + 2 A g (s) + 2 O H^{-} (a q)

E_{A g^{+} / A g}^{\circ} = + 0.80 V

E_{Z n^{2 +} / Z N}^{\circ} = - 0.76 V

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