Calculate the pressure of H, gas taken in the form of gas electrode in a galvanic cell having 1.0 M HCl at `25^(@)C`. Other electrode is that of Ni dipped in 1.0 M `Ni^(2+)` solution. The observed e.m.f. of the cell is 0.245 V.
`E_(Ni^(2+) //Ni) ^(Theta) = -0.25V, E_(2H^(+)//H_(2))^(Theta)= 0.0V`

Explanation

To solve the problem, we will use the Nernst equation to find the pressure of hydrogen gas in the galvanic cell. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the half-reactions and their standard potentials
The half-reactions involved in the galvanic cell are:
1. Oxidation at the anode (Nickel):
\[ \text{Ni} \rightarrow \text{Ni}^{2+} + 2e^- \quad (E^\circ = -0.25 \, \text{V}) \]
...