Some statements about Lechlanche cell are (I) Anode is zinc metal (II) Cathode is graphite rod surrounded by…

Some statements about Lechlanche cell are (I) Anode is zinc metal (II) Cathode is graphite rod surrounded by powdered $\mathrm{MnO}_2$ and carbon (III)Electrolyte is a moist paste of $\mathrm{ZnO}$ and $\mathrm{KOH}$ (IV)Oxidation product is $\mathrm{ZnO}$ The correct statements are
  1. I \& II only
  2. II \& III only
  3. I \& IV only
  4. I, II \& III only

Solution

Lechlunche cell:- Anode : $\mathrm{Zn}$ Container $\mathrm{Zn}(\mathrm{s}) \rightarrow \mathrm{Zn}^{2+}$ (aq.) $+2 \mathrm{e}^{-}$ Cathode: Carbon (graphite) $+\mathrm{MnO}_2+$ Carbon powder. $\mathrm{MnO}_2+\mathrm{NH}_4^{+}+\mathrm{e}^{-} \rightarrow \mathrm{MnO}(\mathrm{OH})+\mathrm{NH}_3$ Electrolyte $=\mathrm{NH}_4 \mathrm{Cl}+\mathrm{ZnCl}_2$ paste Thus, I and II are correct.

Asked in: AP EAMCET 2023 (18 May Shift 1)

Practice more Electrochemistry questions on Aicharya