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TS EAMCET · Chemistry · Electrochemistry

The standard reduction potentials of \(\mathrm{Zn}^{2+}\left|\mathrm{Zn}, \mathrm{Cu}^{2+}\right| \mathrm{Cu}\) and \(\mathrm{Ag}^{+} \mid \mathrm{Cu}\) and \(\mathrm{Ag}^{+} \mid \mathrm{Ag}\) are respectively \(-0.76,0.34\) and \(0.8 \mathrm{~V}\). The following cells were constructed : (1) \(\mathrm{Zn}\left|\mathrm{Zn}^{2+}\right|\left|\mathrm{Cu}^{2+}\right| \mathrm{Cu}\) (2) \(\mathrm{Zn}\left|\mathrm{Zn}^{2+}\right|\left|\mathrm{Ag}^{+}\right| \mathrm{Ag}\) (3) \(\mathrm{Cu}\left|\mathrm{Cu}^{2+} \| \mathrm{Ag}^{+}\right| \mathrm{Ag}\) What is the correct order of \(E_{\text {cell }}^{\circ}\) of these cells?

  1. A \(2>3>1\)
  2. B \(2>1>3\)
  3. C \(1>2>3\)
  4. D \(3>1>2\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(2>1>3\)

Step-by-step Solution

Detailed explanation

Given \(\mathrm{Zn}^{2+} \longrightarrow \mathrm{Zn} \quad E^{\circ}=-0.78 \mathrm{~V}\) \(\mathrm{Cu}^{2+} \longrightarrow \mathrm{Cu} \quad E^{\circ}=0.34 \mathrm{~V}\) \(\mathrm{Ag}^{+} \longrightarrow \mathrm{Ag} \quad E^{\circ}=0.8 \mathrm{~V}\) Cell reaction of (1) is…