Question

Assertion : For the Daniel cell, $Zn\left| Zn^{2+}\right|\left| Cu^{2+}\right| Cu$ with $E_{\text{cell}} = 1 . 1\, V$, the application of opposite potential greater than $1 . 1\, V$ results into flow of electron from cathode to anode.
Reason : $Zn$ is deposited at anode and $Cu$ is dissolved at cathode.

• A. If both assertion and reason are true and reason is the correct explanation of the assertion
• B. If both assertion and reason are true but reason is not the correct explanation of the assertion
• C. If assertion is true, but reason is false
• D. Both assertion and reason are false statements

Answer 1

Answer: (B)

Both (A) and (R) are correct but (R) is not the correct explanation of (A) .
Correct explanation: 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 $Cu$ (cathode to anode) and electrons flow from $Cu$ and $Zn$.
$Zn$ is deposited at $Zn$ electrode and $Cu$ dissolves at $Cu$ electrode.
The reaction is: $Zn ^{2+}+ Cu \rightarrow Zn + Cu ^{2+}$