# A 5% solution (by mass) of cane sugar in water has freezing point of 271 K. Calculate the freezing point of a 5% glucose (by mass) in water. The fre

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A 5% solution (by mass) of cane sugar in water has freezing point of 271 K. Calculate the freezing point of a 5% glucose (by mass) in water. The freezing point of pure water is 273.15 K.

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Correct Answer - 269.07 K
W_(2)=5g,W_(solution)=100g, Mw_(2)=342g
(C_(12)H_(22)O_(11))
First case
W_(1)=100-5=95g
DeltaT_(f)=273.15-271=2.15K
DeltaT_(f)=K_(f)xx(W_(2)xx1000)/(Mw_(2)xxW_(1))
2.15=K_(f)xx(5xx1000)/(342xx95)
Solve forK_(f)impliesK_(f)=13.97
Second case
W_(2)=5g, W_(1)=95g,  ltbr. Mw_(2) of glucose (C_(6)H_(12)O_(6))=180g
DeltaT_(g)=13.97xx(5xx1000)/(180xx95)=4.085
273.15-T_(2)=4.085
T_(2)=273.15-4.085=269.07K