Question

Calculate the ΔrG0 value for the reaction. Given E0(Cr3+/Cr) = -0.74 V ; E0 ( Cd2+/Cd) = -0.40 V , F= 96500 C mol-1)

Answer 1

Answer:

–196.86 kJ

Explanation:

2Cr – 6e– > 2Cr3+

3Cd2+ + 6e– > Cd

Complete reaction : 2Cr+ 3Cd2+ > 2Cr3+ + Cd

E° cell =E° (Cr/Cr3+) + E°(Cd2+/Cd)

= –E°(Cr3+/Cr) + E°(Cd2+/Cd)

= –(–0.74) + (–0.40)

= +0.34 V

ΔrG°= –nFE°cell

= –6×96500×0.34

= –196860 J = –196.86 kJ