JEE Main 2014 · 6 Apr · Shift 1 · Chemistry Q35

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ChemistrySingle correct+4 / -1Question 35 of 90

Resistance of 0.2 M solution of an electrolyte is 50 Ω. The specific conductance of the solution is 1.4 S m $^{-1}$ . The resistance of 0.5 M solution of the same electrolyte is 280 Ω. The molar conductivity of 0.5 M solution of the electrolyte in S m $^2$ mol $^{-1}$ is :

5\times10^{-4}

5\times10^{-3}

5\times10^{3}

5\times10^{2}

Answer and worked solution

Official answer: A

Cell constant. $G^*=\kappa R=1.4\times50=70$ m⁻¹.

At 0.5 M. $\kappa=\dfrac{70}{280}=0.25$ S m⁻¹, and $c=0.5$ mol L⁻¹ $=500$ mol m⁻³. So
$\Lambda_m=\frac{0.25}{500}=5\times10^{-4}\text{ S m}^2\text{ mol}^{-1}.$

Topics:Conductance and Kohlrausch's law

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JEE Main 2014 · 6 Apr · Shift 1, Chemistry question 35