Question

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. The two couples in their standard states are connected to make a cell. The cell potential will be ______.

Options

• +1.19 V

• +0.89 V

• +0.18 V

• +1.83 V

Answer 1

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. The two couples in their standard states are connected to make a cell. The cell potential will be +0.89 V.

Explanation:

The cell is represented as: Cr/Cr²⁺|| Sn⁴⁺/Sn²⁺

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