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JEE Mains · Chemistry · STD 12 - 2. Electrochemistry

Given below are the half-cell reactions : \(Mn^{2+} +2e- \rightarrow Mn;\, E^o = -1.18\,V\) \(2(Mn^{3+} +e^- \rightarrow Mn^{2+} )\,;\,E^o=+1.51\,V\) The \(E^o\) for \(3Mn^{2+} \rightarrow Mn+ 2Mn^{3+}\) will be :

  1. A \(-2.69\, V;\) the reaction will not occur
  2. B \(-2.69\,V; \) the reaction will occur
  3. C \(-0.33\, V;\) the reaction will not occur
  4. D \(-0.33 V;\) the reaction will occur
Verified Solution

Answer & Solution

Correct Answer

(A) \(-2.69\, V;\) the reaction will not occur

Step-by-step Solution

Detailed explanation

(a) \(\quad M n^{2+}+2 e^{-} \rightarrow M n ; \quad E^{\circ}=-1.18 V ; \ldots(i)\) (b) \(\quad M n^{3+}+e \rightarrow M n^{2+} ; \quad E^{\circ}=-1.51 V ; \ldots(i i)\) Now multiplying equation \((i i)\) by two and subtracting from equation \((i)\)…