Statement A: For a cell reactionZn(s)+Cu2+(aq)→Zn2+(aq)+Cu(s); at the equilibrium, voltmeter gives zero reading.Statement B: At the equilibrium, there is no change in the concentration of Cu2+ and Zn2+.

Zn(s)+Cu2+(aq)→Zn(aq)2++Cu(s)As the time passes, the concentration of Zn2+ keeps on increasing while the concentration of Cu2+ keeps on decreasing. At the same time voltage of the cell keeps on decreasing. When there is no change in concentration of Cu2+ and Zn2+ ions, voltmeter gives zero reading and this state is known as equilibrium. At equillibrium magnitude of elctrode potential of both the electrodes becomes equal  and opposite in sign