If the molar conductivities at infinite dilution for $CH_3COOK, K_2SO_4$ and $H_2SO_4$ are respectively, z, y and x ($S\, cm^2\, mol^{-1}$), the molar conductivity of $CH_3COOH$ at infinite dilution will be: |
$(x - y + 2z)/2$ $(x - 2y +2z)/2$ $(x -y-z)$ $(2x + y +2z)$ |
$(x - y + 2z)/2$ |
The correct answer is Option (1) → $(x - y + 2z)/2$ Given:
Step 1: Express Λ₀ using ionic contributions CH₃COOK → CH₃COO⁻ + K⁺ $\Lambda_0(CH_3COOK) = \lambda_0(CH_3COO^-) + \lambda_0(K^+) = z$ K₂SO₄ → 2 K⁺ + SO₄²⁻ $\Lambda_0(K_2SO_4) = 2 \lambda_0(K^+) + \lambda_0(SO_4^{2-}) = y$ H₂SO₄ → 2 H⁺ + SO₄²⁻ $\Lambda_0(H_2SO_4) = 2 \lambda_0(H^+) + \lambda_0(SO_4^{2-}) = x$ Step 2: Express Λ₀(CH₃COOH → CH₃COO⁻ + H⁺) $\Lambda_0(CH_3COOH) = \lambda_0(CH_3COO^-) + \lambda_0(H^+)$ Step 3: Express λ₀(K⁺) and λ₀(SO₄²⁻) from K₂SO₄ $\lambda_0(SO_4^{2-}) = y - 2 \lambda_0(K^+)$ $\lambda_0(CH_3COO^-) = z - \lambda_0(K^+)$ Also from H₂SO₄: $\lambda_0(H^+) = \frac{x - \lambda_0(SO_4^{2-})}{2} = \frac{x - (y - 2 \lambda_0(K^+))}{2} = \frac{x - y + 2 \lambda_0(K^+)}{2}$ Step 4: Λ₀(CH₃COOH) $\Lambda_0(CH_3COOH) = \lambda_0(CH_3COO^-) + \lambda_0(H^+) = (z - \lambda_0(K^+)) + \frac{x - y + 2 \lambda_0(K^+)}{2}=\frac{x - y + 2z}{2}$ |