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Solutions · Question 16

NEET (UG) 2020MCQEasy📈 Topic in 38% papers+4−1
1

The mixture which shows positive deviation from Raoult's law is :

  1. Benzene + Toluene
  2. Acetone + Chloroform
  3. Chloroethane + Bromoethane
  4. Ethanol + Acetone

Answer

(4) Ethanol + Acetone

Solution

As per NCERT, in pure ethanol the molecules are hydrogen bonded. On adding acetone, its molecules get in between the ethanol molecules and break some of the hydrogen bonds.

the A–B interactions are weaker than A–A and B–B interactions

the escaping tendency of molecules increases, so the mixture shows positive deviation from Raoult's law.

Benzene + toluene and chloroethane + bromoethane form nearly ideal solutions.

Acetone + chloroform form hydrogen bonds with each other negative deviation.

Answer: (4)

NEET (UG) 2020

Keep practising — Solutions

2

For an ideal solution, the correct option is :

  1. mix H = 0 at constant T and P
  2. mix G = 0 at constant T and P
  3. mix S = 0 at constant T and P
  4. mix V 0 at constant T and P
NEET (UG) 2019
3

The mixture that forms maximum boiling azeotrope is :

  1. Ethanol + Water
  2. Acetone + Carbon disulphide
  3. Heptane + Octane
  4. Water + Nitric acid
NEET (UG) 2019
4

If molality of the dilute solution is doubled, the value of molal depression constant (Kf) will be

  1. halved
  2. tripled
  3. unchanged
  4. doubled.
NEET 2017
5

Which of the following is dependent on temperature?

  1. Molarity
  2. Mole fraction
  3. Weight percentage
  4. Molality
NEET 2017
6

Which of the following statements about the composition of the vapour over an ideal 1 : 1 molar mixture of benzene and toluene is correct? Assume that the temperature is constant at 25 . (Given, vapour pressure data at 25 , benzene = 12.8 kPa, toluene = 3.85 kPa)

  1. The vapour will contain equal amounts of benzene and toluene.
  2. Not enough information is given to make a prediction.
  3. The vapour will contain a higher percentage of benzene.
  4. The vapour will contain a higher percentage of toluene
NEET 2016 (Phase 1)
7

At 100 the vapour pressure of a solution of 6.5 g of a solute in 100 g water is 732 mm. If Kb = 0.52, the boiling point of this solution will be

  1. 102
  2. 103
  3. 101
  4. 100
NEET 2016 (Phase 1)
8

The van't Hoff factor (i) for a dilute aqueous solution of the strong electrolyte barium hydroxide is

  1. 0
  2. 1
  3. 2
  4. 3
NEET 2016 (Phase 2)
9

Which one of the following is incorrect for ideal solution?

  1. Hmix = 0
  2. Umix = 0
  3. P = Pobs - Pcalculated by Raoult's law = 0
  4. Gmix = 0
NEET 2016 (Phase 2)
10

What is the mole fraction of the solute in a 1.00 m aqueous solution?

  1. 1.770
  2. 0.0354
  3. 0.0177
  4. 0.177
AIPMT 2015
11

The boiling point of 0.2 mol kg-1 solution of X in water is greater than equimolal solution of Y in water. Which one of the following statements is true in this case?

  1. Molecular mass of X is less than the molecular mass of Y.
  2. Y is undergoing dissociation in water while X undergoes no change.
  3. X is undergoing dissociation in water.
  4. Molecular mass of X is greater than the molecular mass of Y.
AIPMT 2015 (Cancelled)

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