Prove the following

Question:

Identify the incorrect statement from the options below for the above cell:

  1. If $\mathrm{E}_{\mathrm{ext}}>1.1 \mathrm{~V}, \mathrm{Zn}$ dissolves at $\mathrm{Zn}$

    electrode and $\mathrm{Cu}$ deposits at $\mathrm{Cu}$ electrode

  2. If $\mathrm{E}_{\text {ext }}>1.1 \mathrm{~V}, \mathrm{e}^{-}$flows from $\mathrm{Cu}$ to $\mathrm{Zn}$

  3. If $\mathrm{E}_{e x t}=1.1 \mathrm{~V}$, no flow of $\mathrm{e}^{-}$or current occurs

  4. If $\mathrm{E}_{\mathrm{ext}}<1.1 \mathrm{~V}, \mathrm{Zn}$ dissolves at anode and $\mathrm{Cu}$ deposits at cathode


Correct Option: 1,

Solution:

$\mathrm{E}_{\text {cell }}^{\mathrm{o}}=0.34-(-0.76)$

$=1.10 \mathrm{volt}$

If $E_{e x t}>1.10$ volt

$\mathrm{Cu} \rightarrow$ Anode

$\mathrm{Zn} \rightarrow$ Cathode

If $\mathrm{E}_{\mathrm{ext}}=1.10$ volt

$\mathrm{Zn} \rightarrow$ Anode

$\mathrm{Cu} \rightarrow$ Cathode

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