Question

At certain Hill-station pure water boils at $99.72$ $^\circ C$ . If $K_{b}$ for water is $0.513$ $^\circ Ckgmol^{- 1}$ . The boiling point of $0.69 \, m$ solution of urea will be-

• A. $100.074$ $^\circ C$
• B. $103$ $^\circ C$
• C. $100.359$ $^\circ C$
• D. Un predictable

Answer 1

Answer: (A)

$\Delta T_{b}=K_{b}\times m$
$=0.513\times 0.69$
$\therefore \Delta T_{b}=0.354$
So, $T_{b}=0.354+99.72=100.074$ $^\circ C$