Liquids having less boling point have high vapour pressure , so is that so with increasing altitude vapour vapour increass as boiling point decreases with height??

the fumdamental is that when the vapour pressuer becomes equal to the outer surrounding pressure the liquid boils...

when the gap betweeen vapour pressure and surrounding pressure is less it is easy for vapour pressure to attain the surrounding pressure value by incresing temprature.

at high altitudes the vapour pressure dosent changes. but the surrounding pressure decreses. so the gap between the vapour pressuer and surrounding pressure decreses leading to lower boiling point