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JEE Main 2025 (Online) 22nd January Evening ShiftMCQMedium📈 Topic in 8% papers+4−1
Ques. 1JEE Main 2025, 22 January (Evening Shift)

Density of 3 M NaCl solution is 1.25 g/mL. The molality of the solution is :

  1. 2.79 m
  2. 2 m
  3. 1.79 m
  4. 3 m

Answer

(1) 2.79 m

Solution

Take 1 L: mass of solution =1250 g, NaCl =3 58.5=175.5 g

⇒ water =1074.5 g =1.0745 kg

∴ m= 31.0745=2.79 m

Answer: (1)

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Ques. 2JEE Main 2026, 8 April (Evening Shift)

Given below are two statements : Given : Molar mass of C, H, O, Cl are 12, 1, 16 and 35.5 g mol-1, respectively In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
Ques. 3JEE Main 2026, 8 April (Evening Shift)

Which of the following statements are not correct? Choose the correct answer from the options given below :

  1. A and B only
  2. A and D only
  3. A, B and D only
  4. A, C and D only
Ques. 4JEE Main 2026, 6 April (Morning Shift)

When 0.25 moles of a non-volatile, non-ionizable solute was dissolved in 1 mole of a solvent the vapor pressure of solution was x% of vapor pressure of pure solvent. What is x% ?

  1. 50%
  2. 60%
  3. 70%
  4. 80%
Ques. 5JEE Main 2026, 6 April (Evening Shift)

Given below are two statements : [figure] In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
Ques. 6JEE Main 2026, 5 April (Morning Shift)

What is the mole fraction of water in 10% by weight (w/w) of aqueous urea solution? [Given: Molar mass of H, O, C and N are 1, 16, 12 and 14 g mol-1 respectively.]

  1. 0.825
  2. 0.032
  3. 0.867
  4. 0.967
Ques. 7JEE Main 2026, 5 April (Evening Shift)

20 g hemoglobin in a 1 L aqueous solution (A) at 300 K is separated from pure water by semi permeable membrane. At equilibrium the height of solution in a tube dipped in a solution (A) is found to be 80.0 mm higher than the tube dipped in water. The molar mass of hemoglobin is kg mol-1. (Nearest integer) (Given : g = 10 m s-2, R = 8.3 kPa dm3 K-1 mol-1, density of solution = 1000 kg m-3)

Ques. 8JEE Main 2026, 4 April (Morning Shift)

A non-volatile, non-electrolyte solid solute when dissolved in 40 g of a solvent, the vapour pressure of the solvent decreased from 760 mm Hg to 750 mm Hg. If the same solution boils at 320 K, then the number of moles of the solvent present in the solution is . (Nearest integer) [Given: boiling point of the pure solvent = 319.5 K, Kb of the solvent = 0.3 K kg mol-1]

Ques. 9JEE Main 2026, 4 April (Evening Shift)

At 27 °C, 0.1 M, 1 L K4[Fe(CN)6] aqueous solution and 0.1 M, 1 L FeCl3 aqueous solution are placed in a container separated by a semi permeable membrane AB. Assume complete dissociation of both the solutes. Which of the following statement is correct? [figure]

  1. Blue color is formed on both sides.
  2. Ionic solutes in aqueous solution can pass through semi-permeable membrane.
  3. Solution on side 'y' is hypotonic.
  4. To cause the reverse flow of solvent during osmosis, external pressure (any value) should be applied to side 'x'.
Ques. 10JEE Main 2026, 2 April (Morning Shift)

19.5 g of fluoro acetic acid (molar mass = 78 g mol-1) is dissolved in 500 g of water at 298 K. The depression in the freezing point of water was 1°C. What is Ka of fluoro acetic acid ? (For water, Kf = 1.86 K kg mol-1). Assume molarity and molality to have same values.

  1. 10-6
  2. 4 10-4
  3. 3 10-5
  4. 3 10-3
Ques. 11JEE Main 2026, 2 April (Evening Shift)

Solution A is prepared by dissolving 1 g of a protein (molar mass = 50,000 g mol-1) in 0.5 L of water at 300 K. Its osmotic pressure is x bar. Solution B is made by dissolving 2 g of the same protein in 1 L of water at 300 K. Osmotic pressure of solution B is y bar. Entire solution of A is mixed with entire solution of B at the same temperature. The osmotic pressure of resultant solution is z bar. x, y and z respectively are: (R = 0.083 L bar mol-1 K-1)

  1. 9.96 10-4; 9.96 10-4; 9.96 10-4
  2. 9.96 10-4; 9.96 10-4; 19.92 10-4
  3. 4.98 10-4; 4.98 10-4; 9.96 10-4
  4. 4.98 10-4; 4.98 10-4; 4.98 10-4

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