What is vapor pressure?
Vapor pressure is defined as force exerted by the gas or vapor released by a liquid or solid substance in a closed container or space. i.e, It is a relative measure of the tendency to evaporate (volatility), and it depends on the nature of the substance and ambient temperature, and reaches a state of equilibrium (where no more vapors escape from the substance) in closed spaces.
The vapor pressure is an indication of a liquid's evaporation rate. It relates to the tendency of particles to escape from the liquid (or a solid). A substance with a high vapor pressure at normal temperatures is often referred to as volatile.