Pressure exerted by saturated water vapour is called aqueous tension. What correction term will you apply to the total pressure to obtain pressure of dry gas ?

Explanation

Whenever a gas is collected over water, it is moist and saturated with water vapours which exert their own pressure. The pressure due to water vapours is called aqueous tension thus, the total pressure of the gas (p moist gas) is
`p_("moist gas")=p_("dry gas")+ "aqueous tension"`
Thus, `p_("dry gas")` is given as
`p_("dry gas")=p_("moist gas")-` aqueous tension Hence, the correction term applied to the total pressure of the gas in order to obtain pressure of dry gas is p moist gas - aqueous tension.