The reaction
1/2 H₂( g)+AgCl(s) ⇌ H⁺(aq)+Cl⁻(aq)+Ag(s)
occurs in which of the given galvanic cell.

Solution

Chemistry ma’am · 4 steps

Split the reaction into two halves, then look for the cell whose two electrodes do exactly those jobs.

1. Oxidation half. 1/2 H₂ → H⁺ + e⁻. Hydrogen gas is oxidised, so the anode (left side) must be a hydrogen electrode, Pt | H₂(g) | H⁺, dipping in a solution that contains H⁺.
2. Reduction half. AgCl(s) + e⁻ → Ag(s) + Cl⁻. Solid AgCl is reduced, so the cathode (right side) must be the silver–silver chloride electrode, Cl⁻ | AgCl(s) | Ag, not Ag⁺ | Ag.
3. Shared electrolyte. The products H⁺ and Cl⁻ end up in the same solution, so both electrodes dip into one electrolyte that holds both ions: HCl.

   Option	Anode	Cathode	Matches?
   (a)	Ag | AgCl, no H₂	Ag⁺ | Ag	No
   (b)	H₂ in HCl	AgCl | Ag in the same HCl	Yes
   (c)	H₂ in HCl	Ag⁺ | Ag, no AgCl	No
   (d)	H₂ in KCl, no H⁺	AgCl | Ag	No

4. So. Only (b) has a hydrogen electrode and a silver–silver chloride electrode sharing HCl, so its cell reaction is exactly 1/2 H₂ + AgCl → H⁺ + Cl⁻ + Ag.

The idea to keep. To match a reaction to a cell, write its two half-reactions. Oxidation goes on the left, reduction on the right, and every ion in the reaction must be present in the electrolyte.

Answer from the NTA final answer key. Solution by PrepWiser.