Q.

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]

1 III < I < II < IV  
2 I < II < III < IV  
3 II < III < I < IV  
4 II < III < IV < I  

Ans.

(2)

ΔTb=i·kb·m

For dilute solution (M=m)

  Molarity i×m
(I) Mglucose=2.2180×1000125=0.098 0.098×1
(II) MCaCl2=1.9111×1000250=0.068 0.068×3
(III) Murea=960×1000500=0.3 0.3×1
(IV) MAl2(SO4)3=20.5342×1000750=0.08 0.08×5

 

Order of ΔTb=Al2(SO4)3>Urea>CaCl2>Glucose

So order of BP=Al2(SO4)3>Urea>CaCl2>Glucose

So Answer will be I<II<III<IV