The metal-insoluble salt electrode consists of a metal M coated with a porous insoluble salt MX In a solution of `X^(-),` A good example is Ihe silver, silver-chloride electrode for which the half-cell reaction is `AgCI(s)+e Leftrightarrow Ag(s) + CI (aq),` where, the reduction of sold silver chloride produces solid silver and releases chloride ion into solute for the cell
`M(s)|M^(2+) (aq)||Ag^(+) (aq)|Ag(s)" "E_(M//M^(2+))^(@)=+2.37V and E_(Ag//Ag)^(@)=+0.80V`
The reaction: `1/2H_(2) (g) +AgCl(s) to H^(+) (aq)+Cl^(-) (aq)+Ag(s)` occurs in the galvanic cell

Options

A. `Ag|AgCl(s)|KCl(aq)|AgNO_(3)(aq)|Ag`
B. `Pt|H_(2)(g)|HCl(aq)|AgNO_(3)(aq)|Ag`
C. `Pt|H_(2)(g)|HCl(aq)|AgCl(s)|Ag`
D. None of these

Answer

To solve the problem, we need to analyze the given galvanic cell reaction and identify the half-cell reactions occurring at the anode and cathode. We will then represent the cell and determine the correct option based on the provided information.

### Step-by-Step Solution:

**Step 1: Identify the Half-Cell Reactions**
- The overall reaction given is:
\[ \frac{1}{2} H_2(g) + AgCl(s) \rightarrow H^+(aq) + Cl^-(aq) + Ag(s) \]
- This reaction can be divided into two half-reactions: one for oxidation (anode) and one for reduction (cathode).

**Step 2: Determine the Anode Reaction**
- At the anode, oxidation occurs. The reaction for oxidation of hydrogen gas is:
\[ \frac{1}{2} H_2(g) \rightarrow H^+(aq) + e^- \]

**Step 3: Determine the Cathode Reaction**
- At the cathode, reduction occurs. The reduction of silver chloride is represented as:
\[ AgCl(s) + e^- \rightarrow Ag(s) + Cl^-(aq) \]

**Step 4: Write the Cell Representation**
- The cell representation includes the anode and cathode components. The standard representation is:
\[ \text{Pt} | H_2(g) | H^+(aq) || Ag^+(aq) | Ag(s) \]
- Since AgCl is a solid and is involved in the cathode reaction, we can represent it as:
\[ \text{Pt} | H_2(g) | HCl(aq) || AgCl(s) | Ag(s) \]

**Step 5: Match with Given Options**
- From the options provided, we need to find the one that matches our cell representation. The correct option is:
\[ \text{Option 3: Pt | H_2(g) | HCl(aq) || AgCl(s) | Ag(s)} \]

### Final Answer:
The correct option is **Option 3**: Pt | H2(g) | HCl(aq) || AgCl(s) | Ag(s).