Solutions · JEE Main previous year questions

2019 11 questions

1. Q752019 · 12 Apr 2019 · Shift 2

   A solution is prepared by dissolving 0.6 g of urea ($\text{molar mass}=60{\text{ g mol}}^{-1}$) and 1.8 g of glucose ($\text{molar mass}=180{\text{ g mol}}^{-1}$) in 100 mL of water at $27^{\circ }\text{C}$. The osmotic pressure of the solution is : ($\text{R}=0.08206{\text{ L atm K}}^{-1}{\text{ mol}}^{-1}$)

   1. A.8.2 atm
   2. B.2.46 atm
   3. C.4.92 atm
   4. D.1.64 atm
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   Answer: C

2. Q742019 · 10 Apr 2019 · Shift 2

   1 g of a non-volatile non-electrolyte solute is dissolved in 100 g of two different solvents A and B whose ebullioscopic constants are in the ratio of 1 : 5. The ratio of the elevation in their boiling points, $\frac{\Delta T_b(A)}{\Delta T_b(B)}$, is :

   1. A.5 : 1
   2. B.1 : 0.2
   3. C.10 : 1
   4. D.1 : 5
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   Answer: D

3. Q732019 · 9 Apr 2019 · Shift 1

   The osmotic pressure of a dilute solution of an ionic compound XY in water is four times that of a solution of 0.01 M $\mathrm{BaC}{\mathrm{l}}_2$ in water. Assuming complete dissociation of the given ionic compounds in water, the concentration of XY (in $\mathrm{mol}{\mathrm{L}}^{-1}$) in solution is :

   1. A.$4\times 10^{-4}$
   2. B.$6\times 10^{-2}$
   3. C.$4\times 10^{-2}$
   4. D.$16\times 10^{-4}$
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   Answer: B

4. Q782019 · 9 Apr 2019 · Shift 1

   Liquid 'M' and liquid 'N' form an ideal solution. The vapour pressures of pure liquids 'M' and 'N' are 450 and 700 mmHg, respectively, at the same temperature. Then correct statement is: ($x_M$ = Mole fraction of 'M' in solution ; $x_N$ = Mole fraction of 'N' in solution ; $y_M$ = Mole fraction of 'M' in vapour phase ; $y_N$ = Mole fraction of 'N' in vapour phase)

   1. A.$\frac{x_M}{x_N}<\frac{y_M}{y_N}$
   2. B.$(x_M-y_M)<(x_N-y_N)$
   3. C.$\frac{x_M}{x_N}=\frac{y_M}{y_N}$
   4. D.$\frac{x_M}{x_N}>\frac{y_M}{y_N}$
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   Answer: D

5. Q752019 · 9 Apr 2019 · Shift 2

   Molal depression constant for a solvent is $4.0\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$. The depression in the freezing point of the solvent for $0.03\mathrm{mol}\mathrm{k}{\mathrm{g}}^{-1}$ solution of ${\mathrm{K}}_2\mathrm{S}{\mathrm{O}}_4$ is : (Assume complete dissociation of the electrolyte)

   1. A.0.18 K
   2. B.0.24 K
   3. C.0.36 K
   4. D.0.12 K
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   Answer: C

6. Q772019 · 9 Apr 2019 · Shift 2

   HF has highest boiling point among hydrogen halides, because it has :

   1. A.lowest dissociation enthalpy
   2. B.strongest hydrogen bonding
   3. C.lowest ionic character
   4. D.strongest van der Waals' interactions
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   Answer: B

7. Q842019 · 8 Apr 2019 · Shift 2
   
   1. A.
   2. B.
   3. C.
   4. D.
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   Answer: A

8. Q712019 · 12 Jan 2019 · Shift 1

   Freezing point of a 4% aqueous solution of X is equal to freezing point of 12% aqueous solution of Y. If molecular weight of X is A, then molecular weight of Y is -

   1. A.4A
   2. B.2A
   3. C.3A
   4. D.A
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   Answer: C

9. Q662019 · 12 Jan 2019 · Shift 2

   Molecules of benzoic acid $({\mathrm{C}}_6{\mathrm{H}}_5\mathrm{COOH})$ dimerise in benzene. 'w' g of the acid dissolved in 30 g of benzene shows a depression in freezing point equal to 2K. If the percentage association of the acid to form dimmer in the solution is 80, then w is – (Its given that $K_f=5\mathrm{K}\mathrm{kg}\mathrm{mo}{\mathrm{l}}^{-1}$, Molar mass of benzoic acid = $122\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$)

   1. A.1.5 g
   2. B.1.8 g
   3. C.1.0 g
   4. D.2.4 g
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   Answer: D

10. Q642019 · 11 Jan 2019 · Shift 2

    ${\mathrm{K}}_2\mathrm{Hg}{\mathrm{I}}_4$ is 40% ionised in aqueous solution. The value of its van't Hoff factor (i) is:

    1. A.1.6
    2. B.2.2
    3. C.2.0
    4. D.1.8
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    Answer: D

11. Q782019 · 9 Jan 2019 · Shift 1

    Which one of the following statements regarding Henry's law is not correct ?

    1. A.Higher the value of ${\mathrm{K}}_{\mathrm{H}}$ at a given pressure, higher is the solubility of the gas in the liquids
    2. B.Different gases have different ${\mathrm{K}}_{\mathrm{H}}$ (Henry's law constant) values at the same temperature.
    3. C.The partial pressure of the gas in vapour phase is proportional to the mole fraction of the gas in the solution.
    4. D.The value of ${\mathrm{K}}_{\mathrm{H}}$ increases with increase of temperature and ${\mathrm{K}}_{\mathrm{H}}$ is function of the nature of the gas
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    Answer: A