Question

The emf $E^{\circ}$ of the following cells are :
$Ag \left| Ag ^{+}(1\, M ) \| Cu ^{2+}(1\, M )\right| Cu ; E^{\circ}=-0.46\, V $
$Zn \left| Zn ^{2+}(1\, M ) \| Cu ^{2+}(1\, M )\right| Cu ; E^{\circ}=1.10\, V$
emf of the following cell is
$Zn \left| Zn ^{2+}(1\, M ) \| Ag ^{+}(1\, M )\right| Ag$

• A. 0.64 V
• B. 1.10 V
• C. 1.56 V
• D. -0.64 V

Answer 1

Answer: (C)

$E_{ Cu ^{2+} / Cu }^{\circ}-E_{ Ag ^{+} / Ag }^{\circ}=-0.46\, V$ ...(i)
$E_{ Cu ^{2+} / Cu }^{\circ}-E_{ Zn ^{2+} / Zn }^{\circ}=1.10\, V$ ...(ii)
On subtracting Eq (i) from equation (ii), we get
$E_{ Ag ^{+} / Ag }^{\circ}-E_{ Zn ^{2+} / Zn }^{\circ}=+1.56\, V$