Question

Which aqueous solution is expected to have the highest boiling point?

• A. $1.5$ $mFeC{l}_2$
• B. $3.0$ $mC{H}_{3}OH$
• C. $2.5$ $m{C}_6{H}_{12}{O}_6$
• D. $2.5$ $mNaCl$
• E. $1.0$ $mCaC{l}_2$

Answer 1

The correct option is D $2.5$ $mNaCl$

$2.5$ mNaCl aqueous solution is expected to have the highest boiling point.
The elevation in the boiling point is directly proportional to the product
$i\times m$ where 'i' is the vant Hoff factor and 'm' is the molality of the solution.
The product $i\times m$ is maximum for $2.5$ mNaCl.
For $2.5$ mNaCl $i\times m=2\times 2.5=5$ (since 1 molecule of NaCl on complete ionization gives 2 ions, the vant Hoff factor i is 2 for NaCl.)