The elevation of boiling point of a dilute solution is given by which expression, where m is molality and Kb the molal elevation constant?

1. For dilute solutions, $\Delta T_b$ is directly proportional to molality m. 2. Introducing the proportionality constant Kb gives $\Delta T_b = K_b m$. 3. The relation is a product, not a ratio or a sum. _Source: NCERT Class 12 Chemistry Ch 1 "Solutions", p.16_