Question

Statement 1: For a cell reaction
$Zn(s) + Cu^{2+} (aq) \to Zn^{2+} (aq) + Cu(s);$ at the equilibrium,voltmeter gives zero reading.
Statement 2: At the equilibrium, there is no change in the concentration of $Cu^{2+}$ and $Zn^{2+}$.

• A. If both Statement 1 and Statement 2 are true and the statement 2 is the correct explanation of the statement 1.
• B. If both Statement 1 and Statement 2 are true but statement 2 is not the correct explanation of the statement 1.
• C. If Statement 1 is true but Statement 2 is false.
• D. If Statement 1 is false but Statement 2 is true

Answer 1

Answer: (A)

$Zn(s) + Cu^{2+} (aq) \to Zn{2+}_{aq} + Cu (s)$ As the time passes, the concentration of $Zn^{2+}$ keeps on increasing while the concentration of $Cu^{2+}$ keeps on decreasing. At the same time voltage of the cell keeps on decreasing. When there is no change in concentration of $Cu^{2+}$ and $Zn^{2+}$ ions, voltmeter gives zero reading and this state is known as equilibrium.