Question

For the electrochemical cell, $M|M^{+}||X^{-}|X,E_{M^{+}/M}^{\circ }=0.44V$ and $E_{X/X}^{\circ }=0.33V$. From this data we can deduce that__________.

• A. $M+X\to M^{+}+X^{-}$ is the spontaneous reaction
• B. $M^{+}+X^{-}\to M+X$ is the spontaneous reaction
• C. $E_{cell}=0.77V$
• D. $E_{cell}=-0,77V$

Answer 1

Answer: (B)

$M^{+}+X^{-}\to M+X$ is the spontaneous reaction

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

$\to E_{M+/M}^{\circ }=0.44V$, electrode reduction potential of $E_{M+/M}^{\circ }$ is greater than $E_{X^{-}/X}^{\circ }$. Hence, reduction will take place of $M^{+}$.

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

$\Rightarrow E_{cell}^{\circ }=0.44V-0.33V=0.11V$.

EMF of cell is positive, the following reaction of the cell is spontaneous.