Question

State and write the mathematical expression for Dalton’s law of partial pressure and explain it with a suitable example.

Answer 1

Dalton’s law of partial pressure:

1. Statement: The total pressure of a mixture of two or more non-reactive gases is the sum of the partial pressures of the individual gases in the mixture.
2. Explanation:
   Dalton’s law can be mathematically expressed as:
   P_Total = P₁ + P₂ + P₃ …(at constant T and V)
   where, P_Total is the total pressure of the mixture and P₁, P₂, P₃, … are the partial pressures of individual gases 1, 2, 3, … in the mixture.
   For example, consider two non-reactive gases A and B. On mixing the two gases, the pressure exerted by individual gas A in the mixture of both the gases is called partial pressure of gas A (say P₁). Likewise, the partial pressure of gas B is P₂. According to Dalton’s law, the total pressure of the mixture of gas A and B at constant T and V will be given as:
   P_Total = P₁ + P₂
   
3. Schematic illustration of Dalton’s law of partial pressures: