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NEET CHEMISTRYMedium

For a cell reaction involving a two-electron change, the standard Emf of the cell is found to be 0.295 V0.295\text{ V} at 25∘C25^{\circ}\text{C}. The equilibrium constant of the reaction at 25∘C25^{\circ}\text{C} will be:

A

1×10−101 \times 10^{-10}

B

29.5×10−229.5 \times 10^{-2}

C

101010^{10}

D

1×10101 \times 10^{10}

Step-by-Step Solution

The relationship between the standard cell potential (Ecell∘E^{\circ}_{cell}) and the equilibrium constant (KcK_c) at 298 K298\text{ K} (25∘C25^{\circ}\text{C}) is given by the Nernst equation at equilibrium: Ecell∘=2.303RTnFlog⁡Kc=0.059nlog⁡KcE^{\circ}_{cell} = \frac{2.303RT}{nF} \log K_c = \frac{0.059}{n} \log K_c Given: Ecell∘=0.295 VE^{\circ}_{cell} = 0.295\text{ V} n=2n = 2 Substituting the values into the equation: 0.295=0.0592log⁡Kc0.295 = \frac{0.059}{2} \log K_c 0.295=0.0295log⁡Kc0.295 = 0.0295 \log K_c log⁡Kc=0.2950.0295=10\log K_c = \frac{0.295}{0.0295} = 10 Therefore, Kc=1010=1×1010K_c = 10^{10} = 1 \times 10^{10}.

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