Q 31 :

The vapour pressure vs. temperature curve for a solution–solvent system is shown below:

The boiling point of the solvent is ______ °C.         [2023]

Q 32 :

If the boiling points of two solvents X and Y (having same molecular weights) are in the ratio 2 : 1 and their enthalpy of vaporization are in the ratio 1 : 2, then the boiling point elevation constant of X is m times the boiling point elevation constant of Y. The value of m is ________ (Nearest Integer)            [2023]

Q 33 :

An aqueous solution of volume 300 ${\mathrm{cm}}^3$ contains 0.63 g of protein. The osmotic pressure of the solution at 300 K is 1.29 mbar. The molar mass of the protein is ________ g ${\mathrm{mol}}^{-1}$. Given: R = 0.083 L bar ${\mathrm{K}}^{-1}$ ${\mathrm{mol}}^{-1}$                              [2023]

Q 34 :

Solutions of 12 g of non-electrolyte (A) prepared by dissolving it in 1000 mL of water exerts the same osmotic pressure as that of 0.05 M glucose solution at the same temperature. The empirical formula of A is ${\mathrm{CH}}_2\mathrm{O}$. The molecular mass of A is ______ g. (Nearest integer)               [2023]

Q 35 :

A solution is prepared by dissolving 0.3 g of a non-volatile non-electrolyte solute A of molar mass 60 g ${\mathrm{mol}}^{-1}$ and 0.9 g of a non-volatile non-electrolyte solute B of molar mass 180 g ${\mathrm{mol}}^{-1}$ in 100 mL ${\mathrm{H}}_2\mathrm{O}$ at 27°C. Osmotic pressure of the solution will be:

[Given: R = 0.082 L atm ${\mathrm{K}}^{-1}$ ${\mathrm{mol}}^{-1}$]                     [2026]

• 1.23 atm

   

• 1.47 atm

   

• 2.46 atm

   

• 0.82 atm

   

Q 36 :

Elements P and Q form two types of non-volatile, non-ionizable compounds PQ and ${\mathrm{PQ}}_2.$When 1 g of PQ is dissolved in 50 g of solvent ‘A’, ${\mathrm{\Delta T}}_{\mathrm{b}}$ was 1.176 K while when 1 g of ${\mathrm{PQ}}_2$ is dissolved in 50 g of solvent 'A', ${\mathrm{\Delta T}}_{\mathrm{b}}$ was 0.689 K. $(K_b\text{ of ‘A’}=5{\text{ K kg mol}}^{-1})$. The molar masses of elements P and Q $\text{(in g mol⁻¹) }$respectively, are:   [2026]

• 65, 145

   

• 70, 110

   

• 60, 25

   

• 25, 60

   

Q 37 :

Consider the following aqueous solutions.    [2026]

I. 2.2 g Glucose in 125 mL of solution.
II. 1.9 g Calcium chloride in 250 mL of solution.
III. 9.0 g Urea in 500 mL of solution.
IV. 20.5 g Aluminium sulphate in 750 mL of solution.

The correct increasing order of boiling point of these solutions will be:
[Given : Molar mass in g $mol⁻¹$ : H = 1, C = 12, N = 14, O = 16, Cl = 35.5, Ca = 40, Al = 27 and S = 32]

• III < I < II < IV

   

• I < II < III < IV

   

• II < III < I < IV

   

• II < III < IV < I

   

Q 38 :

Consider the above electrochemical cell where a metal electrode (M) is undergoing redox reaction by forming ${\mathrm{M}}^{+}, (\mathrm{M}\to {\mathrm{M}}^{+}+{\mathrm{e}}^{-})$. The cation ${\mathrm{M}}^{+}$ is present in two different concentrations $c_1 and c_2$ as shown above. Which of the following statement is correct for generating a positive  cell potential?  [2026]

• If $c_1$ is present at cathode, then $c_1<c_2$

   

• If $c_1$ is present at anode, then $c_1>c_2$

   

• If $c_1$ is present at anode, then $c_1=c_2$

   

• If $c_1$ is present at cathode, then $c_1>c_2$.

   

Q 39 :

A substance ‘X’ (1.5 g) dissolved in 150 g of a solvent ‘Y’ (molar mass = 300 g $mol⁻¹$) led to an elevation of the boiling point by 0.5 K. The relative lowering in the vapour pressure of the solvent ‘Y’ is ______ $\times 10⁻²$. (nearest integer)

[Given : $K_b$ of the solvent = 5.0 K kg $mol⁻¹]$
Assume the solution to be dilute and no association or dissociation of X takes place in solution.         [2026]

Q 40 :

The osmotic pressure of a living cell is 12 atm at 300 K. The strength of sodium chloride solution that is isotonic with the living cell at this temperature is ______ g $L⁻¹$. (Nearest integer)

Given : R = 0.08 L atm $K⁻¹ mol⁻¹$

Assume complete dissociation of NaCl

(Given : Molar mass of Na and Cl are 23 and 35.5 g $mol⁻¹$ respectively.)           [2026]