Question

In the Daniel cell, $Z n\left |Z n^{2+} \| C u^{2+}\right| C u$, when an external voltage is applied such that $E_{\text {external }} > E_{\text {cell }}$, current flows from_________

• A. Zn to Cu
• B. Cu to Zn
• C. No current flows
• D. data insufficient

Answer 1

Answer: (A)

On applying an external voltage greater than $1.1\, V$ in a Daniell cell, the current flows in the reverse direction i.e., from $Zn$ to $C u$ (cathode to anode) and electrons flow from $Cu$ to $Zn$.
$Zn$ is deposited at $Z n$ electrode and $Cu$ dissolves at Cu electrode. The reaction is
$Z n^{2+}+C u \rightarrow Z n +C u^{2+}$