State Dalton’s law and proved that Partial pressure = Total pressure x mole fraction

Question:3. State Dalton’s law of partial pressure with explanation.

Ans. : Dalton’s law of partial pressure: At constant temperature, in a mixture of gases which do not chemically react with one another, the total pressure of the mis sum of the partial pressure of the constituent gases.

Let, P be the total pressure of a gaseous mixture containing ‘n’ components gass and  f₁, f₂, f₃……. f_n . be the partial pressure of the ‘n’ components respectively. Then from this law-

P = f₁  +  f₂ +  f₃  + ………… +  f_n   ………………………. (i)

Explanation: Let n₁, n₂, and n₃ moles of gases are mixed together in a container of volume V and at constant temperature, and their partial pressure P₁, P₂ and P₃ respectively and of the total pressure mixture is P. Since n₁ mole of the first gas exerts pressure P₁ in volume V at temperature T, then from the ideal gas equation,

Question 4: Prove that “partial pressure = total pressure  mole fraction.”

Ans.: Let n₁, n₂, and n₃ moles of gases are mixed together in a container of volume V and at constant temperature, and their partial pressure P₁, P₂ and P₃ respectively and of the total pressure mixture is P. Since n₁ mole of the first gas exerts pressure P₁ in volume V at temperature T, then from the ideal gas equation,

Partial pressure = Total pressure x mole fraction (Proved).

Or partial pressure of a gas mixture, is equal to the product of its mole fraction X total pressure of the gas mixture.