-Dalton's law of partial pressure states that the total pressure by the mixture of non-reactive gases is equal to the sum of the partial pressures of individual gases. - p‌Total ‌=p1+p2+p3 - Also, pi=χip; where pi and χi are the partial pressure and mole fraction of i‌th ‌ gas respectively and p is the total pressure. - p‌Total ‌=p1+p2+p3 ‌‌=n1‌