Question

Two beakers of capacity 500 mL were taken. One of these beakers, labelled as "A" was filled with 400 mL water whereas the beaker labelled "B" was filled with 400 mL of 2M solution of NaCl. At the same temperature both the beakers ware placed in containers os same material and same capacity as shown in figure.

A. Vapour pressure in container (A) is more than that of container (B)
B. Vapour pressure in container (A) is less than that in container (B)
C. Vapour pressur is equal in both the containers
D. Vapour pressure in container (B) is twice the vapour pressure in container (A)

Answer 1

Correct Answer - A
When salt is added to water to make the solution the vapour pressure of solution get decreasses. This is due to decrease in surface covered by solvent molecule which lead to decrease in number of solvent molecule escaping from the surface corresponding to pure solvent.
Hence, vapour pressure also get reduces.