Question

A voltaic cell is constructed with all reactants and products in their standard states. What happens to the emf of the cell if the concentrations of the products are increased?

A. Decreases

B. Increase

C remains the same

Answer 1

From the Nernst Equation E=E°-0.0592/n(logQ)

Where Q=[products]/[reactants]

=> In general, if the concentrations of reactants increase relative to those of products, the cell reaction becomes more spontaneous and the emf increases.

=> Conversely, if the concentrations of products increase relative to reactants, the emf decreases. As voltaic cell operates, reactants are converted into products, which increases the value of Q and causes the emf to decrease.

So emf decreases (A) is correct.