Question

An aqueous solution containing 1 g of urea boils at 100.25$^\circ$C. The aqueous solution containing 3 gof glucose in the same volume will boil be

• A. 100.75$^\circ$C
• B. 100.5$^\circ$C
• C. 100$^\circ$C
• D. 100.25$^\circ$C

Answer 1

Answer: (D)

Solution of non-electrolyte having same concentration will boil at same same temperature.
$10\, g$ of urea; $m =\frac{\frac{1}{60}}{ v }=\frac{1}{60 v }$
$3\, g$ of glucose; $m =\frac{\frac{3}{180}}{ v }=\frac{1}{60 v }$
We know
$\Delta T _{ b }= k _{ b } \times m$
$\Rightarrow \Delta T _{ b } \propto m$
Here, molarity remains unchanged
Hence, they have the same boiling point.