JEE Main · 2025 · 03 Apr 2025 · Shift 2 · Redox Reactions and Electrochemistry

The standard cell potential

(E_{cell}^{⊖})

of a fuel cell based on the oxidation of methanol in air that has been used to power television relay station is measured as 1.21 V. The standard half cell reduction potential for

O_{2}

(E_{O_{2} / H_{2} O}^{o})

is 1.229 V.

Choose the correct statement:

(A)The standard half cell reduction potential for the reduction of $CO_{2}$ $(E_{CO_{2} / CH_{3} OH}^{o})$ is 19 mV✓ Correct
(B)Oxygen is formed at the anode.
(C)Reactants are fed at one go to each electrode.
(D)Reduction of methanol takes place at the cathode.

Answer: (A)

Solution

In a fuel cell, the standard cell potential is given by

E_{cell}^{\circ} = E_{cathode}^{\circ} - E_{anode}^{\circ}

. At the cathode, oxygen is reduced:

E_{cathode}^{\circ} = 1.229

V. At the anode, methanol is oxidized. Using the equation:

1.21 = 1.229 - E_{anode}^{\circ}

, we get

E_{anode}^{\circ} = 0.019

V = 19 mV. This is the standard reduction potential for the

CO_{2} / CH_{3} OH

half-cell.

JEE Main · 2025 · 03 Apr 2025 · Shift 2 · Single correct option

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JEE Main · 2025 · 03 Apr 2025 · Shift 2 · Redox Reactions and Electrochemistry

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