Question

According to Graham’s law of diffusion, at a given temp the ratio of rates of diffusion $r_A/r_B$ of gases A and B is given by

• A. $\left(\frac{P_A}{P_B}\right){\left(\frac{m_A}{m_B}\right)}^{\frac{1}{2}}$
• B. ${\left(\frac{m_A}{m_B}\right)}^{\frac{1}{2}}\left(\frac{P_B}{P_A}\right)$
• C. $\left(\frac{P_A}{P_B}\right){\left(\frac{m_B}{m_A}\right)}^{\frac{1}{2}}$
• D. ${\left(\frac{m_B}{m_A}\right)}^{\frac{1}{2}}\left(\frac{P_B}{P_A}\right)$

Answer 1

The correct option is C $\left(\frac{P_A}{P_B}\right){\left(\frac{m_B}{m_A}\right)}^{\frac{1}{2}}$

$r\propto P\propto \frac{1}{\sqrt{m}}$ (P=Pressure, m = molecular mass)