# Find the emf of a galvanic cell

What is the emf of a galvanic cell consisting of a Cd2+/Cd half-cell and a Pt/H+/H2 half-cell if [Cd2+] = 0.28 M, [H+] = 0.21 M, and PH2 = 0.62 atm?

What is V?

Do I use the equation:

E = E - (.0257V / n) lnQ

What do I put in for E initial?

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#### Solution Preview

We are looking at these reactions:

Cd2+ + 2e- ---> Cd Eo = - 0.40 V

2H+ + 2e- ---> H2 Eo = 0.00 V

To get a positive voltage in a galvanic cell, reverse the first equation and add to the second:

Cd + 2H+ ---> Cd2+ + H2 ...

#### Solution Summary

Finding the emf of a Cd galvanic cell

$2.19