Question

For the electrochemical cell:

M | M+ || X | X,

E0(M+ | M) = 0.44 V, E0(X | X) = 0.33 V

Which of the following is TRUE for this data?

• $"E"_"cell"^0$ = 0.77V
• $"E"_"cell"^0$ = 0.77V
• [\ce{M^+ + X^- -> M + X}] is a spontaneous reaction.
• [\ce{M + X -> M^+ + X^-}] is a spontaneous reaction.

Answer 1

[\ce{M^+ + X^- -> M + X}] is a spontaneous reaction.

Explanation:

Cell reaction: [\ce{M + X -> M^+ + X^-}]

Anode is M and cathode is X.

$"E"_"cell"^0 = "E"_"cathode"^0 - "E"_"anode"^0$

= 0.33 0.44

= 0.11 V

Since, $"E"_"cell"^0$ is negative, the cell reaction is non-spontaneous.

The reverse reaction, [\ce{M^+ + X^- -> M + X}] is the spontaneous reaction.