The standard emf for the cell using the overall cell reaction below is +0.48 V: Zn(s) + Ni²⁺(aq) → Zn²⁺(aq) + Ni(s)
The emf generated by the cell when [Ni²⁺] = 0.100 M and [Zn²⁺] = 2.25 M is ________ V.

Question

Quizplus · Accepted Answer

The Nernst equation can be used to calculate the cell potential under nonstandard conditions:

Ecell = E°cell - (RT/nF) ln(Q)

where E°cell is the standard cell potential, R is the gas constant, T is the temperature in Kelvin, n is the number of moles of electrons transferred in the balanced equation, F is the Faraday constant, and Q is the reaction quotient.

For the given cell reaction, the number of moles of electrons transferred is 2 (from the coefficients in the balanced equation).

At 298 K, we have:

Ecell = 0.48 V - (0.0257 V/K)(2/2) ln(2.25/0.1) = 0.44 V

Therefore, the answer is (C) 0.44 V.

The Standard Emf for the Cell Using the Overall Cell