Question

Which solution has the highest boiling point temperature ?

• A. 0.1 M MgCl${}_2$
• B. 0.1 M HClO${}_4$
• C. 0.1 M KCl
• D. 0.1 M KOH
• E. 0.1 M LiNO${}_3$

Answer 1

Answer: (A)

0.1 M MgCl${}_2$

0.1 M $MgC{l}_2$ solution has the highest boiling point.
Elevation in the boiling point is a colligative property and depends on the number of solute particles.
1 mole of $MgC{l}_2$ on dissociation in water gives 3 moles of ions.
$MgC{l}_2\to M{g}^{2+}+2C{l}^{-}$
This is maximum number of particles as compared to other solutes.
This results in maximum elevation in the boiling point for the solution and highest boiling point.
Note: 1 mole each of $HCl{O}_4,N{H}_{4}OH,KOH$ and $LiN{O}_3$ on dissociation in water gives 2 moles of ions.