For strong electrolyte $\Lambda_{\mathrm{m}}$ increases slowly with dilution and can be represented by the equation $\Lambda_{\mathrm{m}}=\Lambda^{\circ}_{\mathrm{m}}-\mathrm{A}c^{1/2}$ Molar conductivity values of the solutions of strong electrolyte AB at $18^{\circ}\mathrm{C}$ are given below: | $c[\mathrm{mol}\,\mathrm{L}^{-1}]$ | 0.04 | 0.09 | 0.16 | 0.25 | |---|---|---|---|---| | $\Lambda_{\mathrm{m}}[\mathrm{S}\,\mathrm{cm}^{2}\,\mathrm{mol}^{-1}]$ | 96.1 | 95.7 | 95.3 | 94.9 | The value of constant A based on the above data [in $\mathrm{S}\,\mathrm{cm}^{2}\,\mathrm{mol}^{-1}/(\mathrm{mol}/\mathrm{L})^{1/2}$] unit is

JEE Main · 2026 · 28 Jan 2026 · Shift 2 · Redox Reactions and Electrochemistry

For strong electrolyte

Λ_{m}

increases slowly with dilution and can be represented by the equation

Λ_{m} = Λ_{m}^{\circ} - A c^{1/2}

Molar conductivity values of the solutions of strong electrolyte AB at

1 8^{\circ} C

are given below:

$c [mol L^{- 1}]$	0.04	0.09	0.16	0.25
$Λ_{m} [S cm^{2} mol^{- 1}]$	96.1	95.7	95.3	94.9

The value of constant A based on the above data [in

S cm^{2} mol^{- 1} / (mol / L)^{1/2}

] unit is

Answer: 4

The data fit

Λ_{m} = Λ_{m}^{\circ} - A c

, a straight line of

Λ_{m}

against

c

whose slope is

- A

. Taking two points, at

c = 0.04

(

c = 0.2

)

Λ_{m} = 96.1

and at

c = 0.09

(

c = 0.3

)

Λ_{m} = 95.7

; the drop of

0.4

over an increase of

0.1

c

gives

A = \frac{0.4}{0.1} = 4

. The value of the constant

A

4 S c m^{2} mo l^{- 1} / (mol L^{- 1})^{1/2}

JEE Main · 2026 · 28 Jan 2026 · Shift 2 · Integer answer