Question

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

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

Answer 1

Answer: (C)

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.