Question

Which three relationships are true at equilibrium? Ecell = 0, and ∆G = 0, and Q = K Ecell > 0, and ∆G < 0, and Q = K Ecell < 0, and ∆G < 0, and Q < K Ecell = 0, and ∆G > 0, and Q = K Ecell = 0, and ∆G > 0, and Q > K

Answer 1

The correct answer is option A. i.e. Ecell = 0, and ∆G = 0, and Q = K

Ecell is the cell potential or voltage between the two cells.
∆G is the Gibbs free energy. It is actually a difference in the energies of products and reactants.
K is the equilibrium constant for any reaction.
As you can see from the figure attached, the conditions Ecell = 0, and ∆G = 0, and Q = K favour no reaction, which means, the equilibrium is maintained.