The cell `EMF` is independent of the concentration of the species of the cell in

Options

A. `Feoverset(c-)(|)FeO(s)|KOH(aq)|NiO(s)|Ni_(2)O_(3)(s) overset(o+)(|)Ni`
B. `Pt|(H_(2))|HCl|(Cl_(2))Pt`
C. `Zn|Zn^(2+)||Cu^(2+)|Cu`
D. `Hg,Hg_(2)Cl_(2)|KCl||AgNO_(3)|Ag`

Explanation

To determine the cell in which the electromotive force (EMF) is independent of the concentration of the species, we will analyze the options given in the question step by step.

### Step 1: Analyze Option A
**Cell Reaction:** Fe → Fe²⁺ + 2e⁻ (oxidation) and Ni²⁺ + 2e⁻ → Ni (reduction)

- **Anode Reaction:** Fe oxidizes to Fe²⁺, releasing 2 electrons.
- **Cathode Reaction:** Ni²⁺ gains 2 electrons to become Ni.
- **Net Reaction:** Fe + Ni²⁺ → Fe²⁺ + Ni

In this case, the EMF depends on the concentrations of Fe²⁺ and Ni²⁺ ions. Therefore, **EMF is dependent on concentration**.

### Step 2: Analyze Option B
**Cell Reaction:** H₂ + Cl₂ → 2H⁺ + 2Cl⁻

- **Anode Reaction:** H₂ → 2H⁺ + 2e⁻ (oxidation)
- **Cathode Reaction:** Cl₂ + 2e⁻ → 2Cl⁻ (reduction)

This reaction involves gases (H₂ and Cl₂) and the EMF is determined by the partial pressures of the gases rather than their concentrations in solution. Therefore, **EMF is independent of concentration**.

### Step 3: Analyze Option C
**Cell Reaction:** Zn → Zn²⁺ + 2e⁻ (oxidation) and Cu²⁺ + 2e⁻ → Cu (reduction)

- **Anode Reaction:** Zn oxidizes to Zn²⁺, releasing 2 electrons.
- **Cathode Reaction:** Cu²⁺ gains 2 electrons to become Cu.
- **Net Reaction:** Zn + Cu²⁺ → Zn²⁺ + Cu

In this case, the EMF depends on the concentrations of Zn²⁺ and Cu²⁺ ions. Therefore, **EMF is dependent on concentration**.

### Step 4: Analyze Option D
**Cell Reaction:** Hg + Ag⁺ → Hg²⁺ + Ag

- **Anode Reaction:** Hg → Hg²⁺ + 2e⁻ (oxidation)
- **Cathode Reaction:** Ag⁺ + e⁻ → Ag (reduction)

This reaction also depends on the concentrations of Hg²⁺ and Ag⁺ ions. Therefore, **EMF is dependent on concentration**.

### Conclusion
From the analysis, we find that only **Option B** (H₂ + Cl₂ → 2H⁺ + 2Cl⁻) is the cell in which the EMF is independent of the concentration of the species.

### Final Answer
**The cell EMF is independent of the concentration of the species in Option B.**

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