Question

Since the atomic weights of carbon, nitrogen and oxygen are $12,14$ and $16$ respectively, among the following pairs of gases, the pair that will diffuse at the same rate is

• A. carbon dioxide and nitrous oxide
• B. carbon dioxide and nitrogen peroxide
• C. carbon dioxide and carbon monoxide
• D. carbon dioxide and nitric oxide

Answer 1

Answer: (A)

Since rate of diffusion is inversely proportional to square root of molecular weight of gas, the two gases having same molecular weight have same rate of diffusion. Carbon dioxide $\left(C{O}_2\right)$ and nitrous oxide$\left(N_{2}O\right)$ both have same molecular weight $(44u)$ hence, possess same rate of diffusion.