Question

The standard electrode potential for Sn⁺⁴/Sn⁺² couple is +0.15 V and that for the Cr⁺³/Cr couple is −0.74 V. These two couples in their standard states are connected to make a cell (1 Faraday = 96500 mol⁻¹)

What will be the value of \[\ce{E{^{\circ}_{cell}}}\]?

Options

• +1.19 V

• +0.89 V

• +0.18 V

• +1.83 V

Answer 1

+0.89 V

Explanation:

Given: Sn⁴⁺/Sn²⁺ = +0.15 V

Cr³⁺/Cr = −0.74 V

Since Sn⁴⁺/Sn²⁺ has a higher potential, it acts as the cathode, and Cr³⁺/Cr acts as the anode.

Cell potential is calculated using:

\[\ce{E^{\circ}_{cell} = E^{\circ}_{cathode} - E^{\circ}_{anode}}\]

= 0.15 − (−0.74)

= 0.15 + 0.74

= 0.89 V