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Freezing point, boiling point or osmotic pressure of an electrolyte solution with a given dissociation

This type of question, asked 5 times: 30 Jan 2023, 1 Feb 2023, 13 Apr 2023, 5 Apr 2024, 6 Apr 2024. All 6 questions below, oldest first.

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  1. Question 1

    30 Jan 2023

    144
    Lead storage battery contains 38%38\% by weight solution of H2SO4H_{2}SO_{4}. The van't Hoff factor is 2.67 at this concentration. The temperature in Kelvin at which the solution in the battery will freeze is _ __(Nearest integer). Given Kf=1.8 K kg mol−1K_{f}= 1.8\text{ }K\text{ }kg{\text{ }mol}^{- 1}

  2. Question 2

    1 Feb 2023

    55
    25 mL25\text{ }mL of an aqueous solution of KClKCl was found to require 20 mL20\text{ }mL of 1MAgNO31MAgNO_{3} solution when titrated using K2CrO4K_{2}CrO_{4} as an indicator. What is the depression in freezing point of KClKCl solutions of the given concentration? ____ (Nearest integer). (Given: Kf=2.0 K kg mol−1K_{f}= 2.0\text{ }K\text{ }kg{\text{ }mol}^{- 1} ) Assume 1) 100%100\% ionization and 2) density of the aqueous solution as 1 g mL−11\text{ }g{\text{ }mL}^{- 1}

  3. Question 3

    1 Feb 2023

    147
    20%20\% of acetic acid is dissociated when its 5 g5\text{ }g is added to 500 mL500\text{ }mL of water. The depression in freezing point of such water is ___×10−3 ∘C\_\_\_ \times10^{- 3}\ ^{\circ}C Atomic mass of C,HC,H and OO are 12,1 and 16 a.m.u. respectively. [Given: Molal depression constant and density of water are 1.86 K kg mol−11.86\text{ }K\text{ }kg{\text{ }mol}^{- 1} and 1 g cm−31\text{ }g{\text{ }cm}^{- 3} respectively.

  4. Question 4

    13 Apr 2023

    150
    Sea water contains 29.25%NaCl29.25\% NaCl and 19%MgCl219\%MgCl_{2} by weight of solution. The normal boiling point of the sea water is _____ ∘C\_\_\_\_\_\ ^{\circ}C (Nearest integer) Assume 100%100\% ionization for both NaClNaCl and MgCl2MgCl_{2} Given : Kb(H2O)=0.52 K kg mol−1K_{b}\left( H_{2}O \right)= 0.52\text{ }K\text{ }kg{\text{ }mol}^{- 1} Molar mass of NaClNaCl and MgCl2MgCl_{2} is 58.5 and 95 g95\text{ }g mol−1mol^{- 1} respectively.

  5. Question 5

    5 Apr 2024

    149
    Considering acetic acid dissociates in water, its dissociation constant is 6.25×10−56.25 \times10^{- 5}. If 5 mL5\text{ }mL of acetic acid is dissolved in 1 litre water, the solution will freeze at −x×10−2 ∘C- x \times10^{- 2}\ ^{\circ}C, provided pure water freezes at 0∘C0^{\circ}C. x=x =__________ . (Nearest integer) Given: (Kf)water =1.86 K kg mol−1\left( K_{f} \right)_{\text{water~}}= 1.86\text{ }K\text{ }kg{\text{ }mol}^{- 1}. density of acetic acid is 1.2 g mL−11.2\text{ }g{\text{ }mL}^{- 1} molar mass of water =18 g mol−1= 18\text{ }g{\text{ }mol}^{- 1}. molar mass of acetic acid =60 g mol−1= 60\text{ }g{\text{ }mol}^{- 1}. density of water =1 g cm−3= 1\text{ }g{\text{ }cm}^{- 3} Acetic acid dissociates as
    CH3COOH⇌CH3COO⊕+H⊕CH_{3}COOH \rightleftharpoons CH_{3}COO^{\oplus}+H^{\oplus}

  6. Question 6

    6 Apr 2024

    51
    Consider the dissociation of the weak acid HX as given below
    HX(aq)⇌H+(aq)+X−(aq),Ka=1.2×10−5HX(aq) \rightleftharpoons H^{+}(aq) +X^{-}(aq),Ka = 1.2 \times10^{- 5}
    [Ka:\left\lbrack K_{a}: \right. dissociation constant ]\rbrack The osmotic pressure of 0.03M0.03M aqueous solution of HXHX at 300 K300\text{ }K is ____ ×10−2\times10^{- 2} bar (nearest integer). [Given: R=0.083 LbarMol−1 K−1R = 0.083\text{ }LbarMol^{- 1}{\text{ }K}^{- 1} ]