Question

For the electrochemical cell,
$M |M^{+} ||X^{-} | X, E^{\circ}\left(M^{+}/M\right) = 0.44V$ and $E^{\circ}\left(X/X^{-}\right) = 0.33V$ From this data, one can deduce that

• A. $M + X \to M^{+} + X^{-}$ is the spontaneous reaction
• B. $M^{+} + X^{-} \to M + X^{-}$ is the spontaneous reaction
• C. $E_{cell} = 0.77 V$
• D. $E_{cell} = -0 .7 7 V$

Answer 1

Answer: (B)

$M |M^{+}|| X |X^{-}$, Cell reaction should be
$M +X \to M^{+} +X^{-}$
$E^{\circ}_{\text{cell}} =E^{\circ}_{\text{cathode}} -E^{\circ}_{\text{anode}} = 0.33 -0.44 = -0.11V$
$\therefore $ Reverse cell reaction should be spontaneous i.e.
$M^{+} +X^{-} \to M +X$