Calculate the vapour- pressure lowering of water when5.67g of glucose, C6H12O6 is dissolved in 25.2 g water at 250C. The vapour pressure of water at 250C is 23.8 mmHg. What is the vapour pressure of the solution?
Answer:
AS both the solution are isotonic they should have same concentrationin mole/litre
for sucrose solution concentration =4g/100cm3
= 40g/Litre
molar mass of sucrose C 12H22O11 = 342
therefore we get =40/342 moles/litre
For unknown substance Let N be the molecular mass then concentration = 3g/100cm3
= 30g/Litre
= 30/N moles/Litre
comparing the both equation
30/N = 40/342
N=(30 x 342)/40
N= 256.5
Molecular mass of oragnic compound
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