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COMEDK · Chemistry · 18. Electrochemistry

Aluminium displaces hydrogen from dilute \(\mathrm{HCl}\), whereas silver does not. The emf of a cell prepared by combining \(\mathrm{Al} / \mathrm{Al}^{3+}\) and \(\mathrm{Ag} / \mathrm{Ag}^{+}\) is \(2.46 \mathrm{~V}\). The reduction potential of silver electrode is \(+0.80 \mathrm{~V}\). The reduction potential of aluminium electrode is

  1. A \(3.26 \mathrm{~V}\)
  2. B \(-1.66 \mathrm{~V}\)
  3. C \(+1.66 \mathrm{~V}\)
  4. D \(-3.26 \mathrm{~V}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(-1.66 \mathrm{~V}\)

Step-by-step Solution

Detailed explanation

\(E^{\circ}=E_{\left(\mathrm{Ag}^{+} / \mathrm{Ag}\right)}^{\circ}-E_{(\mathrm{Al}}\) \(\begin{aligned} &2.46=0.80-E_{\left(\mathrm{Al}^{3+} / \mathrm{Al}\right)}^{0} \\ &\therefore \quad E_{\left(\mathrm{Al}^{3+} / \mathrm{Al}\right)}^{0}=-1.66 \mathrm{~V} \end{aligned}\)…