JEE Main 2026 Jan 22 Shift 2, Chemistry Q17: Electrochemical Cell And Nernst Equation

JEE Main2026Jan 22, Shift 2Chemistry

Consider the following reduction processes :

$A l^{3 +} + 3 e^{-} \to A l (s)$ , $E^{\circ} = - 1.66$ V

$F e^{3 +} + e^{-} \to F e^{2 +}$ , $E^{\circ} = + 0.77$ V

$C o^{3 +} + e^{-} \to C o^{2 +}$ , $E^{\circ} = + 1.81$ V

$C r^{3 +} + 3 e^{-} \to C r (s)$ , $E^{\circ} = - 0.74$ V

The tendency to act as reducing agent decreases in the order :

Solution

Reducing power is inversely related to the standard reduction potential — the more negative $E^{\circ}$ , the stronger the reducing agent.

Order of $E^{\circ}$ : $A l^{3 +} / A l (- 1.66) < C r^{3 +} / C r (- 0.74) < F e^{3 +} / F e^{2 +} (+ 0.77) < C o^{3 +} / C o^{2 +} (+ 1.81)$ .

Hence reducing power: $A l > C r > F e^{2 +} > C o^{2 +}$ .

Concept behind this question

Concept-wise practice with instant solutions on Fundamenthol.