Question

For the electrochemical cell,$M\left|M^{+}\right|\left|X\right|X^{-}$, $E_{M^{+}/M}^0=0.44\text{V}$and $E_{X/X^{-}}^0=0.33\text{V}$
From these data one can deduce that:

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

Answer 1

The correct option is B $M^{+}+X^{-}\to M+X$ is a spontaneous reaction

$M|M^{+}||X|X^{-}$
$E_{M^{+}/M}^o$ = 0.44
$E_{X/X^{-}}^o$ = 0.33

$M\to M^{+}+E^{-}$ --- (1)

$X+e^{-}\to X^{-}$ ---- (2)

Adding 1 and 2

$M+X\to M^{+}+X^{-}$

$E^o=E_R^o-E_L^o$

$=-0.11$

$\Delta G^o=-nF{E}^o$

$=+ve$

Therefore the reaction is spontaneous in opposite direction

$M^{+}+X^{-}\to M+X$