Question

The difference between the boiling point and freezing point of an aqueous solution containig sucrose in 100 g water

Answer 1

Answer:

According to Table 13.8.1, the molal boiling point elevation constant for water is 0.51°C/m. Thus a 1.00 m aqueous solution of a nonvolatile molecular solute such as glucose or sucrose will have an increase in boiling point of 0.51°C, to give a boiling point of 100.51°C at 1.00 atm.

Answer 2

CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2009

question_answer The difference between the boiling point and freezing point of an aqueous solution containing sucrose (molecular wt = 342 gmol−1) in 100 g of water is105.0∘C. Ifkfandkbof water are 1.86 and0.51 K kg mol−1 espectively, the weight of sucrose in the solution is about

A) 34.2 g

B) 342 g

C) 7.2 g

D) 72 g

E) 68.4 g

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Correct Answer: D

Solution :

Given, Tb−Tf=105.0∘C ⇒(100+ΔTb)−(0−ΔTf)=105∘C ∴ ΔTb+ΔTf=5 ΔTb+ΔTf=(kb+kf)×m(m=molality) ⇒ 5=(1.86+0.51)×w×1000342×100 ∴ w=171023.7=72g