For a general redox reaction Anode $\quad \operatorname{Red}_{1} \rightarrow \mathrm{Ox}_{1}{ }^{\mathrm{n}_{1}^{+}}+\mathrm{n}_{1} \mathrm{e}^{-}$ Cathode $\mathrm{Ox}_{2}+\mathrm{n}_{2} \mathrm{e}^{-} \rightarrow \operatorname{Red}_{2}{ }^{\mathrm{n}_{2}-}$ Which of the following statement is incorrect?

(D) If the reaction is carried out reversibly, the electrical work done is equal to the ratio of charge and potential difference through which charge is moved.

(A) The overall reaction can be written as $\mathrm{n}_{2} \operatorname{Red}_{1}+\mathrm{n}_{1} \mathrm{Ox}_{2} \rightleftharpoons \mathrm{n}_{2} \mathrm{Ox}_{1}^{\mathrm{n}_{1}^{+}}+\mathrm{n}_{1} \operatorname{Red}_{2}{ }^{\mathrm{n}_{2}-}$

(B) The electrons do not appear in the overall reaction because electrons produced at the anode are consumed at the cathode.

JEE Main · 2026 · 06 Apr 2026 · Shift 2 · Redox Reactions and Electrochemistry

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For a general redox reaction

Anode

Red_{1} \to Ox_{1}^{n_{1}^{+}} + n_{1} e^{-}

Cathode

Ox_{2} + n_{2} e^{-} \to Red_{2}^{n_{2} -}

Which of the following statement is incorrect?

(A)The overall reaction can be written as $n_{2} Red_{1} + n_{1} Ox_{2} ⇌ n_{2} Ox_{1}^{n_{1}^{+}} + n_{1} Red_{2}^{n_{2} -}$
(B)The electrons do not appear in the overall reaction because electrons produced at the anode are consumed at the cathode.
(C)(see structure)
(D)If the reaction is carried out reversibly, the electrical work done is equal to the ratio of charge and potential difference through which charge is moved.✓ Correct

Answer: (D)

Solution

Balancing the electrons lost and gained gives the overall reaction

n_{2} Re d_{1} + n_{1} O x_{2} ⇌ n_{2} O x_{1}^{n_{1} +} + n_{1} Re d_{2}^{n_{2} -}

, and because the electrons released at the anode are consumed at the cathode they do not appear in the overall equation; the Nernst plot of

\frac{E - E ^{\circ}}{R T / F}

against

lo g Q

is a straight line whose slope varies as

\frac{1}{n}

. The reversible electrical work is the product of the charge moved and the potential difference,

W = n F E_{ce l l}

, so the statement equating this work with the ratio of charge to potential difference is the wrong one.

JEE Main · 2026 · 06 Apr 2026 · Shift 2 · Single correct option

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JEE Main · 2026 · 06 Apr 2026 · Shift 2 · Redox Reactions and Electrochemistry

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