Q125 / 200 · MHT CET - Medical 2026 (26 April Shift 1) · Chemistry

Calculate the conductivity of $0.025$ M $\text{BaCl}_2$ solution if the molar conductivity of salt at $25^\circ\text{C}$ is $325\ \Omega^{-1}\ \text{cm}^2\ \text{mol}^{-1}$.

  • A
    $8.125 \times 10^{-2}\ \Omega^{-1}\text{cm}^{-1}$
  • Correct answer
    B
    $8.125 \times 10^{-3}\ \Omega^{-1}\text{cm}^{-1}$
  • C
    $7.6923 \times 10^{-2}\ \Omega^{-1}\text{cm}^{-1}$
  • D
    $8.372 \times 10^{-2}\ \Omega^{-1}\text{cm}^{-1}$

Solution

Given:
Concentration, $C = 0.025\ \text{M}$
Molar conductivity, $\Lambda_m = 325\ \Omega^{-1}\ \text{cm}^2\ \text{mol}^{-1}$

The relationship between molar conductivity and conductivity ($\kappa$) is given by:
$\Lambda_m = \dfrac{\kappa \times 1000}{C}$

Rearranging the formula to solve for $\kappa$:
$\kappa = \dfrac{\Lambda_m \times C}{1000}$

Substituting the given values:
$\kappa = \dfrac{325 \times 0.025}{1000}$

$\kappa = \dfrac{8.125}{1000}$

$\kappa = 8.125 \times 10^{-3}\ \Omega^{-1}\ \text{cm}^{-1}$

Answer: $8.125 \times 10^{-3}\ \Omega^{-1}\text{cm}^{-1}$

Hence, the correct answer is option: 'B'.

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