After adding non-volatile solute freezing point of water decrease

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 Multiple Choice QuestionsMultiple Choice Questions

161.

Osmotic pressure of the solution can be increased by,

  • increasing the temperature of the solution

  • decreasing the temperature of the solution

  • increasing the volume of the vessel

  • diluting the solution


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162.

After adding non-volatile solute freezing point of water decreases to -0.186C. Calculate ΔTb if Kf = 1.86 K kg mol-1 and Kb =0.521 K kg mol-1.

  • 0.521

  • 0.0521

  • 1.86

  • 0.0186


B.

0.0521

According to Raoult's law, when a non-volatile solid is added to the solvent its vapour pressure decreases and now its vapour pressure would become equal to that of solid solvent at lower temperature. Thus, the freezing point of the solvent decreases.

ΔTf ∝ m (m = molality of solution)

ΔT= Kf m, 0.186 = 1.86 × m

m= 0.1

Now ΔTb = Kb × m = 0.521 × 0.1 = 0.0521


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163.

Which of the following has the lowest freezing point?

  • 0.1 m sucrose

  • 0.1 m urea

  • 0.1 m ethanol

  • 0.1 m glucose


164.

A litre of solution is saturated with AgCl. To this solution if 1.0 × 10-4 mole of solid NaCl is added, what will be the [Ag+], assuming no volume change ?

  • More

  • Less

  • Equal

  • Zero


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165.

The vant Hoffs factor 'i' accounts for

  • extend of solubility

  • extent of mobility of solute

  • extent of dissolution of solute

  • extent of dissociation of solute


166.

When the pure solvent diffuses out of the solution through the semi-permeable membrane then the process is called

  • sorption

  • dialysis

  • reverse osmosis

  • osmosis


167.

Which has the minimum freezing point ?

  • One molal NaCl aq. solution

  • One molal CaCl2 aq. solution

  • One molal KCl aq. solution

  • One molal urea aq. solution


168.

Which of the following aqueous solution has highest freezing point?

  • 0.1 molal Al2(SO4)3

  • 0.1 molal BaCl2

  • 0.1 molal AlCl3

  • 0.1 molal NH4Cl


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169.

If a solution containing 0.072 g atom of sulphur in 100 g of a solvent (kf = 7.0) gave a freezing point depression of 0.84°C, the molecular formula of sulphur in the solutions is :

  • S6

  • S7

  • S8

  • S9


170.

Which one of the following is not correct for an ideal solution ?

  • It must obey Raoult's law

  • H = 0

  • C = 0

  • H = V  0


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