Medium MCQ +4 / -1 PYQ · JEE Mains 2025

On charging the lead storage battery, the oxidation state of lead changes from $x_1$ to $y_1$ at the anode and from $x_2$ to $y_2$ at the cathode. The values of $x_1, y_1, x_2, y_2$ are respectively :

  1. A $0,+2,+4,+2$
  2. B $+2,0,0,+4$
  3. C $+4,+2,0,+2$
  4. D $+2,0,+2,+4$ Correct answer

Solution

<p>For charging of lead storage battery cell reaction is</p> <p>$$2 \mathrm{PbSO}_4(\mathrm{~s})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{Pb}(\mathrm{~s})+\mathrm{PbO}_2(\mathrm{~s})+2 \mathrm{H}_2 \mathrm{SO}_4(\mathrm{aq})$$</p> <p>At anode $\mathrm{PbSO}_4$ reduced back to Pb and at cathode $\mathrm{PbSO}_4$ oxidised back to $\mathrm{PbO}_2$.</p> <p>$$\begin{aligned} \because ~& \mathrm{x}_1=+2, \mathrm{y}_1=0 \\ \mathrm{x}_2 & =+2, \mathrm{y}_2=4 \end{aligned}$$</p>

About this question

Subject: Chemistry · Chapter: Electrochemistry · Topic: Electrochemical Cells

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