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JEE Advanced

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Q 1. An azeotropic solution of two liquids has boiling point lower than either of them when it

A

shows negative deviation from Raoult's law

B

shows no deviation from Raoult's law

shows positive deviation from Raoult's law

D

is saturated

Explanation

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Q 2. For a dilute solution, Raoult's law states that :

A

the lowering of vapour pressure is equal to the mole fraction of solute.

the relative lowering of vapour pressure is equal to the mole fraction of solute.

C

the relative lowering of vapour pressure is proportional to the amount of solute in solution.

D

the vapour pressure of the solution is equal to the mole fraction of solvent.

Explanation

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Q 3. The molecular weight of benzoic acid in benzene as determined by depression in freezing point method corresponds to :

A

ionization of benzoic acid.

dimerization of benzoic acid.

C

trimerization of benzoic acid.

D

solvation of benzoic acid.

Explanation

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Q 4. The Henry's law constant for the solubility of {tex} \mathrm { N } _ { 2 } {/tex} gas in water at {tex} 298 \mathrm { K } {/tex} is {tex} 1.0 \times 10 ^ { 5 } \mathrm { atm } {/tex}. The mole fraction of {tex} \mathrm { N } _ { 2 } {/tex} in air is {tex} 0.8 . {/tex} The number of moles of {tex} \mathrm { N } _ { 2 } {/tex} from air dissolved in 10 moles of water at {tex} 298 \mathrm { K } {/tex} and {tex}5{/tex} atm pressure is

{tex} 4.0 \times 10 ^ { - 4 } {/tex}

B

{tex} 4.0 \times 10 ^ { - 5 } {/tex}

C

{tex} 5.0 \times 10 ^ { - 4 } {/tex}

D

{tex} 4.0 \times 10 ^ { - 6 } {/tex}

Explanation

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Q 5. Pure water freezes at {tex} 273 \mathrm { K } {/tex} and {tex}1 \mathrm{ bar}{/tex}. The addition of {tex} 34.5 \mathrm { g } {/tex} of ethanol to {tex} 500 \mathrm { g } {/tex} of water changes the freezing point of the solution. Use the freezing point depression constant of water as {tex} 2 \ \mathrm { K }\ \mathrm { kg }\ \mathrm { mol } ^ { - 1 } {/tex}. The figures shown below represent plots of vapour pressure (V.P.) versus temperature (T). [ molecular weight of ethanol is {tex} \left. 46\ \mathrm { g }\ \mathrm { mol } ^ { - 1 } \right] {/tex} Among the following, the option representing change in the freezing point is

A

B

D

Explanation

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Q 6.

The ratio of the value of any colligative property for solution to that of sugar solution is

A

1

B

0.5

2

D

4

Explanation

Van’t Hoff factor

For it is 2 and for sugar it is 1

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Q 7.

What would be the freezing point of aqueous solution containing 17 g of in 1000 g of water.

B

C

D

Explanation

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Q 8.

The osmotic pressure of a solution (density is 1 g ) containing 3 g of glucose (molecular weight = 180) in 60 g of water at is

A

B

D

Explanation

atm

Weight of solution Density

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Q 9.

The molal freezing point constant of water is 1.86 K , If 342 g of cane sugar ( is dissolved in 1000 g of water, the solution will freeze at

B

C

D

Explanation

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Q 10.

On mixing 10 mL of acetone with 40 mL of chloroform, the total volume of the solution is

B

C

D

Cannot be predicted

Explanation

The interparticle forces in between and acetone increase due to H-bonding and thus becomes negative

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Q 11.

The most likely of the following mixtures to be an ideal solution is

B

C

D

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Q 12.

on reaction with in aqueous solution gives blue colour. These are separated by a semi-permeable membrane AB as shown. Due to osmosis, there is

A

Blue colour formation in side X

B

Blue colour formation in side Y

C

Blue colour formation in both of sides X and Y

No blue colour formation

Explanation

Osmosis of water and not of ion takes place

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Q 13.

A mixture of volatile components A and B has total vapour pressure (in torr)

Where is the mole fraction of A in mixture. Hence, and are (in torr)

A

254, 119

B

119, 254

135, 254

D

154, 119

Explanation

Given

Compare with the given equation,

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Q 14.

An azeotropic solution of two liquids has boiling point lower than either of them when it

A

Shows negative deviation from Raoult’s law

B

Shows no deviation from Raoult’s law

Shows positive deviation from Raoult’s law

D

Is saturated

Explanation

Azeotropic mixtures are also known as constant boiling mixtures. They are liquid mixtures which boil over without any change in the composition. Such mixtures cannot be separated into components by fractional distillation. They are of two types: maximum boiling azeotropes and minimum boiling azeotropes

Maximum boiling azeotropes are formed by solutions having negative deviations. Boiling point is maximum

For example,

  • Water and

  • Water and nitric acid

  • Chloride form and acetone

  • Acetic acid and pyridine

  • Minimum boiling azeotropes are formed by solutions having positive deviations. Boiling point is minimum. For example,

  • Acetic acid and toluene

  • Pyridine and water

  • Ethanol and benzene

  • Water and ethanol

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    Q 15.

    Which has the maximum osmotic pressure at temperature ?

    A

    100 mL of 1 m urea solution

    B

    300 mL of 1 M glucose solution

    C

    Mixture of 100 mL of 1 M urea solution and 300 mL of 1 M glucose solution

    All are isotonic

    Explanation

  • (mix has concentration =1 M)

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    Q 16.

    A 5% solution of cane sugar (molecular weight = 342) is isotonic with 1% solution of substance X. The molecular weight of X is

    A

    171.2

    68.4

    C

    34.2

    D

    136.2

    Explanation

    For non-electrolytic solution, if isotonic,

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    Q 17.

    A teacher one day pointed out to his students the peculiar fact that water is a unique liquid which freezes exactly at and boils exactly at . He asked the students to find the correct statement based on this fact

    A

    Water dissolves anything, however sparingly the dissolution may be

    B

    Water is a polar molecule

    Boiling and freezing temperatures of water were used to define a temperature scale

    D

    Liquid water is denser than ice

    Explanation

    The scaling of zero degree centigrade is based on this fact

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    Q 18.

    The vapour pressure (VP) of a dilute solution of non-­volatile solute is and the VP of a pure solvent is . The lowering of the VP is

    B

    C

    D

    Explanation

    Lowering is always positive

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    Q 19.

    The osmotic pressure of a solution increases if

    A

    Temperature is lowered

    B

    Volume is increased

    Number of solute molecules is increased

    D

    None of the above

    Explanation

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    Q 20.

    On mixing 10 mL of carbon tetrachloride with 10 mL of benzene, the total volume of the solution is

    A

    B

    D

    Cannot be predicted

    Explanation

    No changes in interparticle forces as both are non-polar

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    Q 21.

    Azeotropic mixtures are

    Constant boiling point mixture without changing the composition

    B

    Those which boil at different temperatures

    C

    Mixtures of two solids

    D

    None of the above

    Explanation

    The definition of azeotropic mixture

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    Q 22.

    A solution containing 4 g of a non-volatile organic solute, per 100 mL was found to have an osmotic pressure equal to 500 cm of mercury at . The molecular weight of solute is

    A

    14.97

    149.7

    C

    1697

    D

    1.497

    Explanation

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    Q 23.

    When 20 g of naphthoic acid ( ) is dissolved in 50 g of benzene ( ), a freezing point depression of 2 K is observed. The van’t Hoff factor (i) is

    0.5

    B

    1

    C

    2

    D

    3

    Explanation

    Actual molecular weight of naphthoic acid ( )=172

    Molecular mass (calculated)

    = =344

    van’t Hoff factor (i) =

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    Q 24.

    When a solution is separated from a solvent by a semi-permeable membrane, then the phenomenon taking place is called as

    Osmosis

    B

    Diffusion

    C

    Solubility

    D

    None

    Explanation

    The movement of solvent particles from dilute solution to concentrated one through a semi-permeable membrane is called osmosis

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    Q 25.

    A mixture of benzene and toluene forms

    An ideal solution

    B

    Non-ideal solution

    C

    Suspension

    D

    Emulsion

    Explanation

    Mixing of benzene and toluene does not involve any kind of decrease or increase in interaction forces in between molecules