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Molality from the depression in freezing point or elevation of boiling point

This type of question, asked 14 times: 2 May 2023 S1, 3 May 2023 S1, 9 May 2023 S2, 16 May 2023 S2, 12 May 2024 S1, 13 May 2024 S2, 20 Apr 2025 S2, 21 Apr 2025 S1, 23 Apr 2025 S1, 25 Apr 2025 S1, 26 Apr 2025 S1, 16 Apr 2026 S2, 18 Apr 2026 S1, 19 Apr 2026 S1. All 14 questions below, oldest first.

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  1. Question 1

    2 May 2023 S1

    82
    Calculate the molality of solution of non-volatile solute having depression in freezing point 0.93 K and cryoscopic constant of solvent 1.861.86 K kg mol−1^{-1}.

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  2. Question 2

    3 May 2023 S1

    51
    A solution of non-volatile solute has boiling point elevation 1.75 K. Calculate molality of solution [Kb=3.5 K kg mol−1K_b=3.5\ \text{K kg mol}^{-1}]

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  3. Question 3

    9 May 2023 S2

    58
    A solution of non-volatile solute has boiling point elevation 0.5 K. Calculate molality of solution Kb=2.40K_b = 2.40 K kg mol−1^{-1}.

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  4. Question 4

    16 May 2023 S2

    93
    Calculate the molality of solution if its depression in freezing point is 0.18 K. Kf=1.6K_f = 1.6 K kg mol−1^{-1}

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  5. Question 5

    12 May 2024 S1

    99
    Calculate molality of solution of a non-volatile solute having boiling point elevation 1.89 K if boiling point elevation constant of solvent is 3.15 K kg mol−13.15\,\text{K kg mol}^{-1}.

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  6. Question 6

    13 May 2024 S2

    83
    What is the molality of solution of a nonvolatile solute having boiling point elevation 7.15 K and molal elevation constant 2.75 K kg mol−12.75\ \text{K kg mol}^{-1}?

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  7. Question 7

    20 Apr 2025 S2

    83
    Calculate the molality of nonvolatile solution if solution freezes at −0.95∘C-0.95^{\circ}C [Kf\left\lbrack K_{f} \right. for water, =1.86 K mol−1= 1.86\text{ }K{\text{ }mol}^{- 1}, freezing point of water =0∘C=0^{\circ}C ]

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  8. Question 8

    21 Apr 2025 S1

    98
    Calculate molality of the solution containing nonvolatile solute if boiling point elevation of the solution is 0.2 K [Kb=0.52 K kg mol−1]\left\lbrack K_{b}= 0.52\text{ }K\text{ }kg{\text{ }mol}^{- 1} \right\rbrack

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  9. Question 9

    23 Apr 2025 S1

    94
    Calculate the molality of solution of nonvolatile solute if boiling point elevation is 1.75 K. [Kb\left\lbrack K_{b} \right. for solvent  =3 K kg mol−1]\left. \ = 3\text{ }K\text{ }kg{\text{ }mol}^{- 1} \right\rbrack

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  10. Question 10

    25 Apr 2025 S1

    88
    Calculate the molality of the solution containing nonvolatile solute if boiling point elevation of solution is 0.39 K . [ KbK_{b} of water =0.52 K kg mol−1= 0.52\text{ }K\text{ }kg{\text{ }mol}^{- 1} ]

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  11. Question 11

    26 Apr 2025 S1

    97
    Calculate the molality of the solution of nonvolatile solute if it freezes at −0.36∘C-0.36^{\circ}C. [KfK_{f} for solvent =1.86 K kg mol−1= 1.86\text{ }K\text{ }kg{\text{ }mol}^{- 1}]

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  12. Question 12

    16 Apr 2026 S2

    23
    The normal boiling point of Ethyl acetate is 77∘C77^\circ\mathrm{C}. A solution of non-volatile non-electrolyte solute in ethyl acetate boils at 78∘C78^\circ\mathrm{C}. KbK_b for ethyl acetate is 2.77 ∘C kg mol−12.77\ ^\circ\mathrm{C\,kg\,mol^{-1}}. What is the molality of the solution ?

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  13. Question 13

    18 Apr 2026 S1

    23
    Calculate the molality of solution of nonvolatile solute if boiling point of solution, molal elevation constant for solvent are 319.8319.8 K and 2.5 K kg mol−12.5\ \mathrm{K\,kg\,mol^{-1}} respectively [Boiling point of solvent = 319.5319.5 K]

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  14. Question 14

    19 Apr 2026 S1

    22
    A solution of non volatile solute has boiling point elevation 0.700.70 K if KbK_b for the solvent is 2.44 K kg mol−12.44\ \mathrm{K\,kg\,mol^{-1}}. What is the molality of the solution?

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