RE-NEET 2026 Chemistry Conductance & Molar Conductivity MCQ Question

To find the limiting molar conductivity of the Y⁻ ion, we use the relationship:

$\Lambda_m = \Lambda^0_{x^+} + \Lambda^0_{y^-} - k \sqrt{C}$

where $k$ is the slope of the plot, and $C$ is the concentration. Given $\Lambda_m = 145.0 \, \text{S cm}^2 \text{mol}^{-1}$ at $C = 0.01 \, \text{M}$ and $k = 90.0 \, \text{S cm}^2 \text{mol}^{-3/2} \text{L}^{1/2}$, we can rearrange to find $\Lambda^0_{y^-}$:

$\Lambda^0_{y^-} = \Lambda_m + k \sqrt{C} - \Lambda^0_{x^+}$

Substituting the values:

$\Lambda^0_{y^-} = 145.0 + 90.0 \times 0.1 - 74.0 = 145.0 + 9.0 - 74.0 = 80.0 \, \text{S cm}^2 \text{mol}^{-1}$

Thus, the limiting molar conductivity of Y⁻ is 80.0 S cm² mol⁻¹. Other options fail because they do not satisfy the equation with the given values.