Boiling point is the temperature at which a liquid changes its state and starts to vaporize. The boiling point of a solution depends on the concentration and nature of the solute. In this context, we will compare the boiling point of two solutions - 0.1M NaCl and 0.1M glucose and explain why one has a higher boiling point than the other.



The boiling point of a solution is higher than that of a pure solvent. This phenomenon is known as boiling point elevation and is due to the presence of solute particles in the solution. The more the concentration of solute particles, the greater the boiling point elevation.



The extent of boiling point elevation depends on the Van't Hoff factor (i), which is the ratio of the number of particles in a solution to the number of moles of solute dissolved. For ionic compounds like NaCl, i is greater than 1 as it dissociates into ions in solution. On the other hand, for molecular compounds like glucose, i is equal to 1 as it does not dissociate into ions.



The 0.1M NaCl solution has a higher boiling point than the 0.1M glucose solution due to the following reasons:

• The Van't Hoff factor of NaCl is 2, which means that there are two particles in solution for every mole of NaCl dissolved - one Na+ ion and one Cl- ion. In contrast, the Van't Hoff factor of glucose is 1, which means that there is only one glucose molecule in solution for every mole of glucose dissolved.


• Since NaCl dissociates into ions, the solute particles attract more solvent molecules through ion-dipole forces, which increases the boiling point of the solution.


• In contrast, glucose is a non-electrolyte and does not dissociate into ions. Therefore, it does not attract solvent molecules as strongly, leading to a lower boiling point elevation.

In summary, the 0.1M NaCl solution has a higher boiling point than the 0.1M glucose solution due to the higher Van't Hoff factor and stronger ion-dipole forces between the solute particles and solvent molecules.