At constant volume and temperature conditions,the rate of diffusion $D_A$ and $D_B$ of gases $A$ and $B$ having densities $\rho_A$ and $\rho_B$ are related by the expression:

• A
  $D_A = D_B (\frac{\rho_A}{\rho_B})^{1/2}$
• B
  $D_A = D_B (\frac{\rho_B}{\rho_A})$
• C
  $D_A = D_B (\frac{\rho_A}{\rho_B})$
• D
  $D_A = D_B (\frac{\rho_B}{\rho_A})^{1/2}$