It states that if a container contains a mixture of gases which do not react chemically that the total pressure exerted by the system is the sum of the individual partial pressure of the gases.
Total = PA + PB = PC +……
Example: If a system contains gases A, B and C which do not react chemically, fins the total pressure of the system if A, B and C has partial pressures of 10 N/m2. 30N/m2 respectively.
P Total = PA + PB + PC (Dalton’s law of partial pressure)
P Total = 10 + 30 + 40 = 80 N/m2