Question

Assertion :A graph plotted between ${\Lambda }_{m}vs{c}^{1/2}$ gives a straight line with slope equal to $K$ and intercept equal to ${\Lambda }_{\infty }$. Reason: The value of ${\Lambda }_m$ for a given solvent and temperature depends upon the nature of the electrolyte, i.e., charge on cation or anion furnished by an electrolyte on dissolution.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Assertion is incorrect but Reason is correct.

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.

A graph plotted between ${\Lambda }_{m}vs.c^{1/2}$ gives a straight line with slope equal to K and intercept equal to ${\Lambda }_{\infty }$.

The numerical value of conductance ${\Lambda }_{\infty }$ is obtained by extrapolation of ${\Lambda }_{m}vs.\sqrt{c}$ curves to zero concentration for all electrolytes.

This can be seen from the equation ${\Lambda }_m={\Lambda }_{\infty }-K{c}^{1/2}$

Which is an equation of a straight line with slope K and y intercept ${\Lambda }_{\infty }$.

The value of ${\Lambda }_m$ for a given solvent and temperature depends upon the nature of the electrolyte, i.e., charge on cation or anion furnished by an electrolyte on dissolution.

Hence, both Assertion and Reason are correct but Reason is not the correct explanation for Assertion