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JEE Main 2024 (Online) 4th April Evening ShiftNumericalMedium📈 Topic in 14% papers+4
Ques. 1JEE Main 2024, 4 April (Evening Shift)

2.7 kg of each of water and acetic acid are mixed. The freezing point of the solution will be -x C. Consider the acetic acid does not dimerise in water, nor dissociates in water. x = (nearest integer) [Given: Molar mass of water = 18 g mol-1, acetic acid = 60 g mol-1 Kf H2O : 1.86 K kg mol-1 Kf acetic acid: 3.90 K kg mol-1 freezing point: H2O = 273 K, acetic acid = 290 K]

Answer

31

Solution

Moles of water = 270018 = 150

Moles of acetic acid = 270060 = 45

∵ water is in larger amount ⇒ water is the solvent, acetic acid the solute

m = 452.7 = 16.67 mol kg-1

Tf = Kf m = 1.86 16.67 = 31 K

⇒ f.p. = 0 − 31 = −31 °C ∴ x = 31

Answer: 31

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Ques. 2JEE Main 2024, 1 February (Morning Shift)

We have three aqueous solutions of NaCl labelled as 'A', 'B' and 'C' with concentration 0.1 M, 0.01 M and 0.001 M, respectively. The value of van 't Hoff factor (i) for these solutions will be in the order :

  1. iA < iC < iB
  2. iA < iB < iC
  3. iA > iB > iC
  4. iA = iB = iC
Ques. 3JEE Main 2024, 1 February (Evening Shift)

Mass of ethylene glycol (antifreeze) to be added to 18.6 kg of water to protect the freezing point at -24 is kg (Molar mass in g mol-1 for ethylene glycol 62, Kf of water = 1.86 K kg mol-1)

Ques. 4JEE Main 2024, 31 January (Morning Shift)

Identify the mixture that shows positive deviations from Raoult's Law

  1. (CH3)2CO + CS2
  2. (CH3)2CO + C6H5NH2
  3. CHCl3 + C6H6
  4. CHCl3 + (CH3)2CO
Ques. 5JEE Main 2024, 30 January (Morning Shift)

What happens to freezing point of benzene when small quantity of naphthalene is added to benzene?

  1. Increases
  2. Decreases
  3. Remains unchanged
  4. First decreases and then increases
Ques. 6JEE Main 2024, 30 January (Evening Shift)

The solution from the following with highest depression in freezing point/lowest freezing point is

  1. 180 g of acetic acid dissolved in benzene
  2. 180 g of acetic acid dissolved in water
  3. 180 g of benzoic acid dissolved in benzene
  4. 180 g of glucose dissolved in water
Ques. 7JEE Main 2024, 30 January (Evening Shift)

If a substance 'A' dissolves in solution of a mixture of 'B' and 'C' with their respective number of moles as nA, nB and nC. Mole fraction of C in the solution is

  1. nCnA nB nC
  2. nBnA+nB
  3. nCnA+nB+nC
  4. nCnA-nB-nC
Ques. 8JEE Main 2024, 29 January (Morning Shift)

The osmotic pressure of a dilute solution is 7 105 Pa at 273 K. Osmotic pressure of the same solution at 283 K is 104 Nm-2.

Ques. 9JEE Main 2024, 29 January (Evening Shift)

Molality of 0.8 M H2SO4 solution (density 1.06 g cm-3) is 10-3 m.

Ques. 10JEE Main 2024, 27 January (Morning Shift)

A solution of two miscible liquids showing negative deviation from Raoult's law will have :

  1. increased vapour pressure, increased boiling point
  2. increased vapour pressure, decreased boiling point
  3. decreased vapour pressure, decreased boiling point
  4. decreased vapour pressure, increased boiling point
Ques. 11JEE Main 2024, 27 January (Evening Shift)

The quantity which changes with temperature is :

  1. Molality
  2. Molarity
  3. Mole fraction
  4. Mass percentage

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