Read the passage given below and answer the following questions :
Raoult's law states that for a solution of volatile liquids, the partial vapour pressure of each component of the solution is directly proportional to its mole fraction present in solution. Dalton's law of partial pressure states that the total pressure `P_("total")` over the solution phase in the container will be the sum of the partial pressures of the components of the solution and is given as:
`P_("total")`= `P_1`+ `P_2`

A solution of two liquids boils at a temperature more than the boiling point of either of them. What type of deviation will be shown by the solution formed in terms of Raoult' s law ?

Options

A. Negative deviation
B. Positive deviation
C. First positive then negative
D. First negative then positive

Answer

A

Explanation

Since the Boiling point of the solution is more than the boiling point of the individual component in the solution , It indicates that the vapour pressure exerted by the solution is less than the expected , as boiling starts when vapour pressure equals to the atmospheric pressure . Hence ,the solution shows a negative deviation from the Raoult.s law.