Following figure shows dependence of molar conductance of two electrolytes on concentration. $\Lambda^{0}_{\mathrm{m}}$ is the limiting molar conductivity. The number of Incorrect statement(s) from the following is ______ (A) $\Lambda_{\mathrm{m}}^{0}$ for electrolyte A is obtained by extrapolation (B) For electrolyte $B$, $\Lambda_m$ vs $\sqrt{c}$ graph is a straight line with intercept equal to $\Lambda_m^0$ (C) At infinite dilution, the value of degree of dissociation approach zero for electrolyte B. (D) $\Lambda_{\mathrm{m}}^{0}$ for any electrolyte A or B can be calculated using $\lambda^{\circ}$ for individual ions.

JEE Main · 2023 · 29 Jan 2023 · Shift 1 · Redox Reactions and Electrochemistry

Following figure shows dependence of molar conductance of two electrolytes on concentration.

Λ_{m}^{0}

is the limiting molar conductivity.

The number of Incorrect statement(s) from the following is ______
(A)

Λ_{m}^{0}

for electrolyte A is obtained by extrapolation
(B) For electrolyte

B

Λ_{m}

c

graph is a straight line with intercept equal to

Λ_{m}^{0}

Λ_{m}^{0}

for any electrolyte A or B can be calculated using

λ^{\circ}

for individual ions.

Answer: 2

Solution

Curve A climbs steeply as the concentration falls towards zero, the mark of a weak electrolyte whose limiting molar conductivity cannot be read off by straight extrapolation; line B is nearly straight, the behaviour of a strong electrolyte. The claim that

Λ_{m}^{0}

of A is obtained by extrapolation is therefore wrong, and the claim that the degree of dissociation tends to zero at infinite dilution is wrong because there it tends to unity. The statement that B gives a straight

Λ_{m}

against

c

line of intercept

Λ_{m}^{0}

, and that

Λ_{m}^{0}

of either electrolyte can be built from the individual ionic conductivities by Kohlrausch's law, are both sound. The number of incorrect statements is two.

JEE Main · 2023 · 29 Jan 2023 · Shift 1 · Integer answer

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JEE Main · 2023 · 29 Jan 2023 · Shift 1 · Redox Reactions and Electrochemistry

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