Question

Which compounds show negative deviation from Raoult’s law?

Answer 1

Raoult’s law states that the vapor pressure of an ideal solution is directly proportional to the mole fraction of the solvent. If the solutions are not going to follow and show a decrease in the vapor pressure of the solution then it is called negative deviation from Raoult’s law.

Complete answer:
- In the question it is asked to write the examples of the compound which shows the negative deviation from Raoult’s law.
- The compound which has intermolecular bonding like hydrogen bonding in between the atoms is going to show a decrease in vapor pressure of the solution which results in the negative deviation from Raoult’s law.
- The compounds which show negative deviation from Raoult’s law are a mixture of acetone and chloroform.
- On mixing these chemicals results the formation of the hydrogen bonding between the atoms of the molecules.
- Therefore automatically there is a decrease in the vapor pressure of the mixture which results the negative deviation from the Rauolt’s law.
- The mixture of acetone and chloroform is going to show a negative deviation from Raoult's law.
- The bonding between the atoms of the acetone with the atoms of the chloroform is very high when it is mixed with chloroform.

Note:
If the vapor pressure of the solution is going to increase by mixing two different compounds then the solution is going to show a positive deviation from Raoult's law. Means the added solute makes the solvent to evaporate from the solution.