Question

why boiling point increases with pressure ??

Answer 1

using the kinetic theory of matter, increase in pressure leads to increased kinetic energy of the particles collide more hence the increase in boiling point

Answer 2

What happens when water boils? The steam vapor pressure increases with temperature and becomes larger than the room pressure. Then bubbles can form, the steam inside pushes against the room pressure and the bubbles expand, hence the water boils. Therefore, the higher room pressure, the more steam pressure you need, and hence the hotter you must cook the water for it to boil.