Question

A vessel contains 1 mole of O₂ gas (molar mass 32) at a temperature T. The pressure of the gas is P. An identical vessel containing one mole of He gas (molar mass 4) at temperature 2T has a pressure of 

(A) 2 P 

(B) P 

(C) 8 P 

(D) (P/8)

Answer 1

The correct option (A) 2 P

Explanation:

PV = nRT

∴ P = (nRT/V)

as vessel is same, V is constant

n = 1 in both cases

∴ P ∝ T

(P₂ / P₁) = (T₂ / T₁)

T₁ = T & T₂ = 2T, P₁ = P

∴ (P₂ / P) = (2T / T) = 2

∴ P₂ = 2 P