Q27 / 90 · JEE Main 2022 (25 Jun Shift 1) · Chemistry

In a cell, the following reactions take place

Fe2+→Fe3++e-  EoFe3+/Fe2+=0.77 V

2I-→I2+2e-  EI2/I-0=0.54 V

The standard electrode potential for the spontaneous reaction in the cell is x×10-2 V at 298 K. The value of x is - (Nearest Integer)

Correct answer: 23

Solution

The electrode which has more reduction potential will get reduced in spontaneous reaction in the cell. So, spontaneous reaction will be 

2Fe3+aq+2I-aq→2Fe2+aq+I2

Iron will act as cathode and Iodine will act as anode.

E0cell=E0RPC-E0RPA

=0.77-0.54

=0.23 V

=23×10-2 V

Hence, the correct answer is 23.

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