JEE Main 2022 · Chemistry · Electrochemistry · medium

The same current is passed through two electrolytic cells connected in series: AgNO3 solution and CuSO4 solution, both with platinum electrodes. 2.16…

Numerical answer

The same current is passed through two electrolytic cells connected in series:

\mathrm{AgNO_3}

solution and

\mathrm{CuSO_4}

solution, both with platinum electrodes.

2.16\ \mathrm g

of silver (

\mathrm{Ag}=108

) is deposited in the first cell. The total volume of

\mathrm{O_2}

released at the two anodes, in mL at STP (molar volume

22400\ \mathrm{mL}

), is

Show answer and solution

Answer: 224

Charge passed corresponds to

2.16/108=0.020

mol of electrons (one electron per Ag

^+

). In each cell the anode reaction is

2\mathrm{H_2O}\to\mathrm{O_2}+4\mathrm H^++4e^-

, which gives

0.020/4=0.0050

mol of

\mathrm{O_2}

per cell, because the same number of electrons passes through both cells in series. Total

\mathrm{O_2}=0.010

mol

=0.010\times22400=224\ \mathrm{mL}

. (The

\mathrm{Cu}

deposited is

0.635

g, irrelevant for this part.)

Original question written in the JEE Main 2022 pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake