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Degree of dissociation or hydrogen ion concentration of a weak electrolyte from molar conductivities

This type of question, asked 7 times: 9 May 2023 S1, 10 May 2023 S2, 15 May 2023 S2, 11 May 2024 S2, 15 Apr 2026 S1, 20 Apr 2026 S2, 19 May 2026 S1. All 7 questions below, oldest first.

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  1. Question 1

    9 May 2023 S1

    74
    Molar conductivity of 0.02 M weak acid is 7.92 Ω−1 cm2 mol−17.92\,\Omega^{-1}\,\text{cm}^2\,\text{mol}^{-1} and its molar conductivity at infinite dilution is 232.7 Ω−1 cm2 mol−1232.7\,\Omega^{-1}\,\text{cm}^2\,\text{mol}^{-1}. Calculate degree of dissociation of weak acid.

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  2. Question 2

    10 May 2023 S2

    55
    The molar conductivity of 0.01 M acetic acid at 25∘C25^\circ C is 16.5 Ω−1 cm2 mol−116.5\,\Omega^{-1}\,\text{cm}^2\,\text{mol}^{-1} and its molar conductivity at zero concentration is 390.7 Ω−1 cm2 mol−1390.7\,\Omega^{-1}\,\text{cm}^2\,\text{mol}^{-1}. What is its degree of dissociation?

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  3. Question 3

    15 May 2023 S2

    66
    Calculate the percentage dissociation of 0.05 M solution of weak electrolyte if its molar conductivity and molar conductivity at infinite dilution are respectively 3.3 Ω−1cm2mol−13.3\,\Omega^{-1}\text{cm}^2\text{mol}^{-1} and 132 Ω−1cm2mol−1132\,\Omega^{-1}\text{cm}^2\text{mol}^{-1}.

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  4. Question 4

    11 May 2024 S2

    100
    Calculate the degree of dissociation of 0.01 M acetic acid at 25∘C25^{\circ}\text{C}. Λc=15.0 Ω−1cm2mol−1\Lambda_c = 15.0\,\Omega^{-1}\text{cm}^2\text{mol}^{-1} and Λ0=300 Ω−1cm2mol−1\Lambda_0 = 300\,\Omega^{-1}\text{cm}^2\text{mol}^{-1}

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  5. Question 5

    15 Apr 2026 S1

    24
    The molar conductivity of 0.010.01 M monobasic acid at 25 ∘C25\ ^\circ\mathrm{C} is 15 ohm−1 cm2 mol−115\ \mathrm{ohm^{-1}\ cm^2\ mol^{-1}}. The molar conductivity of the same acid at infinite dilution is 375 ohm−1 cm2 mol−1375\ \mathrm{ohm^{-1}\ cm^2\ mol^{-1}}. Calculate [H+][\mathrm{H^+}] in solution.

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  6. Question 6

    20 Apr 2026 S2

    26
    If molar conductance at infinite dilution for CH3COO−\mathrm{CH_3COO^-} and H+\mathrm{H^+} ions are 50 S cm2 mol−150\ \mathrm{S\,cm^2\,mol^{-1}} and 350 S cm2 mol−1350\ \mathrm{S\,cm^2\,mol^{-1}} respectively, molar conductivity of 5×10−25 \times 10^{-2} M CH3COOH\mathrm{CH_3COOH} is 20 S cm2mol−120\ \mathrm{S\,cm^2mol^{-1}}. What is the hydrogen ion concentration in mol/dm3\mathrm{mol/dm^3} of CH3COOH\mathrm{CH_3COOH}?

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  7. Question 7

    19 May 2026 S1

    29
    The molar conductivity of 0.010.01M acetic acid at 25∘C25^\circ\mathrm{C} is 16 S m2 mol−116\ \mathrm{S\ m^2\ mol^{-1}}. Find its percent dissociation in the 0.010.01M solution if molar conductivity of acetic acid at zero concentration is 390 S m2 mol−1390\ \mathrm{S\ m^2\ mol^{-1}}.

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