Question

Define Elevation in boiling point and derive its relation with the molecular mass of non-volatile solute

Answer 1

Elevation in Boiling Point is defined as the increase in the boiling point of a substance on the addition of a non - volatile solute in it.

- Mathematically, it can be represented as:

ΔTb ∝ m

⇒ ΔTb = Kb × m

⇒ ΔTb = Kb × {(w × 1000) / (M.wt × W)}

Or M.wt = (1000 × Kb × w) / (ΔTb × W)

- Both the above highlighted equations are the required relations.

Answer 2

Answer:

Elevation in boiling point is the phenomenon of an increase in the boiling point of a solvent due to the addition of a non-volatile solute. The extent of elevation in boiling point depends on the concentration of the solute and the properties of the solvent.

The elevation in boiling point can be mathematically expressed as ∆Tb = Kb × molality, where ∆Tb is the change in boiling point, Kb is the molal boiling point elevation constant, and molality is the concentration of the solute in mol per kg of solvent.

The relation between the elevation in boiling point and the molecular mass of a non-volatile solute can be derived from the equation mentioned above. It is found that the magnitude of the elevation in boiling point is directly proportional to the molality of the solution and the molal boiling point elevation constant, and is also directly proportional to the molecular mass of the solute. Hence, the larger the molecular mass of the solute, the greater will be the elevation in boiling point.