Practicing Success

Target Exam

CUET

Subject

Chemistry

Chapter

Physical: Electro Chemistry

Question:

What is the EMF of the following cell?

Fe|Fe2+ (0.6M) || Sn2+(0.2M)|Sn    ; EoFe2+/Fe = -0.44 V,  EoSn2+/Sn = 0.14 V

Options:

0.566 V

0.466 V

0.366 V

0.266 V

Correct Answer:

0.566 V

Explanation:

Eocell = EoSn2+/Sn - EoFe2+/Fe = 0.14 - (-0.44) = 0.14 + 0.44 = 0.58 V

Ecell = Eocell - \(\frac{0.059}{2}\)log\(\frac{[Fe^{2+}]}{[Sn^{2+}]}\)

Ecell = 0.58 - 0.0295log\(\frac{[0.6]}{[0.2]}\)

Ecell = 0.58 - 0.0295 x log3

Ecell = 0.58 - 0.0295 x 0.47 = 0.566 V