The first known US drone strike against Al Qaeda operatives took place in Yemen on November 4, 2002. The attack, conducted by the CIA, took out a car carrying six suspected militants, including Abu Ali (a.k.a., Qaed Senyan al-Harthi), a former security guard for Osama bin Laden.
Boiling point is the temperature at which vapour pressure of liquid becomes equal to the atmospheric pressure. More is the vapour pressure lesser will be the heat require to raise its vapour pressure . So more is the vapour pressure lower is the boiling point .
1 Explain that vapor pressure is unaffected by changes in external pressure. 2  Define boiling point as the point at which vapor pressure equals external pressure.  Explain that boiling point declines with elevation due to a decrease in external pressure.