Derive expression to calculate emf (reduction) of the following half cells at `25^@C`
`H^+||H_2(Pt) (1 atm)`

Explanation

To derive the expression for the electromotive force (emf) of the half-cell reaction \( H^+ + e^- \rightarrow H_2(g) \) at \( 25^\circ C \), we can follow these steps:

### Step 1: Identify the Half-Cell Reaction
The half-cell reaction involves the reduction of hydrogen ions (\( H^+ \)) to hydrogen gas (\( H_2 \)). The balanced half-reaction is:
\[ H^+ + e^- \rightarrow H_2(g) \]

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