Question

Which one will have highest boiling point, if $1$ mole of each of the following substances was discovered in $1,000$ grams of water?

• A. NaCl
• B. KCl
• C. $CaC{l}_2$
• D. $C_6{H}_{10}{O}_5$
• E. $C_{12}{H}_{22}{O}_{11}$

Answer 1

The correct option is C $CaC{l}_2$

$CaC{l}_2$ will have the highest boiling point if 1 mole of each of the following substances was discovered in 1,000 grams of water. The boiling point and the elevation in the boiling point is directly proportional to the van't Hoff's factor.
$\Delta T_b=i{K}_{b}m$
Here, $\Delta T_b$ is the elevation in the boiling point, i is the van't Hoff factor, $K_b$ is the molal elevation in boiling point constant and m is the molality of the solution.
1 molecule of $CaC{l}_2$ on dissociation gives three ions in the solution.
$CaC{l}_2\to C{a}^{2+}+2C{l}^{-}$
Since it gives maximum number of ions in solution, it has maximum van't Hoff factor and maximum elevation in the boiling point.