In pure liquid, the entire surface of liquid is occupied by the molecules of water. When a non-volatile solute, e.g., glucose is dissolved in water, the fraction of surface covered by the solvent molecules gets reduced because some positions are occupied by glucose molecules.

So, number of solvent molecules escaping from the surface is reduced. That is why vapour pressure of aqueous solution of glucose is reduced.

When salt is spread over snow covered roads, snow starts melting from the surface because depression of freezing point of water takes place due to addition of salt. It helps in clearing of roads.

Hence, the phenomena is depression in freezing point which helps in clearing the snow covered roads in hilly areas.

Continuous sheets or films (natural or synthetic) which contain a network of submicroscopic holes or pores through which small solvent molecules (water etc.) can pass, but solute molecules of bigger size cannot pass are called semipermeable membrane. e.g., cellophane membrane.

Since pressure required for the reverse osmosis is very high, so, a suitable material is used for making semipermeable membrane. It is generally cellulose acetate placed over suitable support.

A. $\rightarrow$ (4) B. $\rightarrow(3)$ C. $\rightarrow$ (1) D. $\rightarrow$ (2) E. $\rightarrow(6) \quad$ F. $\rightarrow(5)$

A. Saturated solution A solution which contains maximum amounts of solute that can be dissolved in a given amount of solvent at a given temperature.

B. Binary solution A solution with two components is known as binary solution.

C. Isotonic solution A solution having same osmotic pressure at a given temperature as that of given solution is known as isotonic solution.

D. Hypotonic solution A solution whose osmotic pressure is less than another is known as hypotonic solution.

E. Solid solution A solution in solid phase is known as solid solution.

F. Hypertonic solution A solution whose osmotic pressure is greater than that of another is known as hypertonic solution.