A solution of two miscible liquids showing negative deviation from Raoult's law will have :

A solution showing negative deviation from Raoult's law has stronger intermolecular forces between unlike molecules than like molecules.

This results in:

- Decreased vapour pressure (molecules are held more tightly in solution, fewer escape to vapor phase)

- Increased boiling point (higher temperature needed to reach atmospheric pressure since vapour pressure is lower)

The answer is: decreased vapour pressure, increased boiling point, which corresponds to Option (4).