Question

Following figure shows dependence of molar conductance of two electrolytes on concentration. Λ^o _m is the limiting molar conductivity. The number of incorrect statement(s) from the following is ________ 

(A) \(\Lambda \text{o m}\) for electrolyte A is obtained by extrapolation. 
(B) For electrolyte B, \(\Lambda \text{m}\) vs \(\sqrt c\) graph is a straight line with intercept equal to o \(\Lambda \text{m}\)
(C) At infinite dilution, the value of degree of dissociation approaches zero for electrolyte B. 
(D) Λo m for any electrolyte A or B can be calculated using \(\lambda0\) for individual ions.

Hint:

For molar conductance:
Strong electrolytes show a linear dependence of \(\Lambda_m\) on \(\sqrt{C}\), with gradual decreases at higher concentrations.
Weak electrolytes exhibit non-linear dependence due to incomplete ionization, with \(\Lambda_m\) leveling off as concentration increases.

Answer 1

Correct Answer: 2

The figure shows the dependence of molar conductance (Λ_m) on the square root of concentration (√c) for two electrolytes A and B:

• (A) Incorrect: For strong electrolytes (B), Λ_m vs. √c is a straight line, but for weak electrolytes (A), Λ^o_m is obtained by extrapolation as concentration approaches zero.
• (B) Correct: For electrolyte B (strong electrolyte), the graph is linear and the intercept is Λ^o_m.
• (C) Incorrect: At infinite dilution, the degree of dissociation approaches one for electrolyte B, not zero.
• (D) Correct: Λ^o_m for an electrolyte is calculated using λ^o for individual ions (Kohlrausch's law).

Number of incorrect statements = 2.

This result lies within the specified range (2, 2).