Question

When common salt is added to water, the boiling point of water increases.
A) True
B) False

Answer 1

Hint: Recall the colligative property of solutions i.e. elevation in boiling point. When common salt is mixed with water there is an elevation in the boiling point which will result in the increase of the boiling point of water.

Complete step by step answer:
When salt is added to water, then the intermolecular forces between water molecules gets altered due to the dissociation of $NaCl$ into sodium ion (\[N{a^ + }\]) and chloride ions ($C{l^ - }$). The hydrogen bonding between water molecules gets affected and the ion-dipole interaction between sodium ions and chloride ions and dipole (water) starts occurring. Ion-dipole interaction is a comparatively strong bond. Hence more heat is required by water molecules to come out as a gaseous phase and vaporize which will result in rising in the boiling point of the water.
Also when the salt is dissolved in water, the water molecules need more energy to produce enough pressure to escape the boundary of the liquid. The more the salt added more will be the rise in the boiling point.

Hence the given statement is true, so the correct answer is option A.

Note:
Also, remember that Depression in freezing point is also a colligative property. When common salt is mixed with water there is an elevation in the boiling point as well as depression in the freezing point. Due to this, the freezing point of water decreases when common salt is mixed with water. Due to this phenomenon, the salt is being spread on roads full of snow in cold countries to remove it easily.