## More Questions on This Topic :

Question 1. A solution of urea contains 8.6 gm/litre (mol. Wt. 60.0). It is isotonic with a 5% (W/W) solution of a non-volatile solute having density 1 g/cc. The molecular weight of the solute will be
1.    348.8
2.    34.88
3.    3488
4.    861.2
: A

Isotonic solutionshavesameosmoticpressure
As Osmotic pressure = C R T
C1=C2
n1V1=n2V2
5% W/W solutionmeans 100g ofsolution contains 5gofsolute
8.6601=5M1001000
M=5×60×108.6=348.8

Question 2. A non-ideal solution was prepared by mixing 30 ml chloroform and 50 ml acetone. The volume of mixture will be
1.    > 80 ml
2.    = 80 ml
3.    ≥ 80 ml
: B

Chloroform and Acetone solution shows negative deviation from Rault’s law. HenceVmix<0

Question 3. The relative lowering of vapour pressure produced by dissolving 71.5 g of a substance in 1000 g of water is 0.00713. The molecular weight of the substance will be
1.    180
2.    342
3.    60
4.    18.0
: A

P1P01=n2n1+n2n2n1=W2/M2W1/M1

M2=W2×M1W1×(P1P01)=71.5×181000×0.00713=180.5g/mole

Question 4. A 0.001 molal solution of [Pt(NH3)4cl4] in water had a freezing point depression of 0.0054. If Kf  for water is 1.80, the correct formulation for the above molecule is
1.    [Pt(NH3)4Cl3]Cl
2.    [Pt(NH3)4]Cl4
3.    [Pt(NH3)4Cl2]Cl3
4.    [Pt(NH3)4Cl2]Cl2