The reaction;

$$\frac{1}{2} \mathrm{H}_{2(\mathrm{~g})}+\mathrm{AgCl}_{(\mathrm{s})} \rightarrow \mathrm{H}_{(\mathrm{aq})}^{+}+\mathrm{Cl}_{(\mathrm{aq})}^{-}+\mathrm{Ag}_{(\mathrm{s})}$$

occurs in which of the following galvanic cell :

<p>To determine which galvanic cell corresponds to the given reaction:</p> <p>$$\frac{1}{2} \mathrm{H}_{2(\mathrm{~g})}+\mathrm{AgCl}_{(\mathrm{s})} \rightarrow \mathrm{H}_{(\mathrm{aq})}^{+}+\mathrm{Cl}_{(\mathrm{aq})}^{-}+\mathrm{Ag}_{(\mathrm{s})}$$</p> <p>we need to examine the setups of the given cells and check if they produce the same reactants and products as in the above reaction.</p> <p>Analyzing the reaction, we observe:</p> <ul> <li>Hydrogen gas ($\mathrm{H}_{2(\mathrm{~g})}$) is involved at one electrode and splits into $\mathrm{H}_{(\mathrm{aq})}^{+}$ ions.</li> <li>Solid silver chloride ($\mathrm{AgCl}_{(\mathrm{s})}$) decomposes at another electrode into $\mathrm{Ag}_{(\mathrm{s})}$ and $\mathrm{Cl}_{(\mathrm{aq})}^{-}$ ions.</li> </ul> <p>Let's examine each option:</p> <p>Option A:</p> <p>$$\mathrm{Pt}\left|\mathrm{H}_{2(\mathrm{~g})}\right| \mathrm{HCl}_{(\text {soln.) }}\left|\mathrm{AgNO}_{3(\mathrm{aq})}\right| \mathrm{Ag}$$</p> <p>This cell setup does not directly involve $\mathrm{AgCl}_{(\mathrm{s})}$ solid separating into $\mathrm{Ag}_{(\mathrm{s})}$ and $\mathrm{Cl}_{(\mathrm{aq})}^{-}$. Hence, it does not match the reaction given.</p> <p>Option B:</p> <p>$$\mathrm{Ag}\left|\mathrm{AgCl}_{(\mathrm{s})}\right| \mathrm{KCl}_{(\text {(soln.) }}\left|\mathrm{AgNO}_{3 \text { (aq.) }}\right| \mathrm{Ag}$$</p> <p>This involves silver electrodes and does not have a setup for reaction with hydrogen gas or the splitting of $\mathrm{H}_{2(\mathrm{~g})}$ into $\mathrm{H}_{(\mathrm{aq})}^{+}$ ions. So, this does not match either.</p> <p>Option C:</p> <p>$$\mathrm{Pt}\left|\mathrm{H}_{2(\mathrm{~g})}\right| \mathrm{KCl}_{(\text {soln.) }}\left|\mathrm{AgCl}_{(\mathrm{s})}\right| \mathrm{Ag}$$</p> <p>While this configuration includes $\mathrm{AgCl}_{(\mathrm{s})}$ and $\mathrm{H}_{2(\mathrm{~g})}$, it uses potassium chloride solution instead of hydrochloric acid solution, which alters the chemistry and does not perfectly match the required reaction mechanism.</p> <p>Option D:</p> <p>$$\mathrm{Pt}\left|\mathrm{H}_{2(\mathrm{~g})}\right| \mathrm{HCl}_{(\text {soln. })}\left|\mathrm{AgCl}_{(\mathrm{s})}\right| \mathrm{Ag}$$</p> <p>This configuration fits the reaction given. Here hydrogen gas at the platinum electrode splits into $\mathrm{H}_{(\mathrm{aq})}^{+}$ ions in the hydrochloric acid solution. On the other side, the solid silver chloride separates into $\mathrm{Ag}_{(\mathrm{s})}$ and $\mathrm{Cl}_{(\mathrm{aq})}^{-}$ ions. Hence, this accurately matches the reaction.</p> <p>Therefore, the correct answer is:</p> <p>Option D</p>