Under identical conditions of temperature and pressure, the ratio of the rates of effusion of O₂ and CO₂ gases is given by:

Temperature and pressure are constant

Molar mass of oxygen =(2×16)g/mole

Molar mass of carbon dioxide=44g/mole

Now,

According to graham's law of diffusion

Rate of diffusion is inversely proportional to the square root of molar mass

$$\begin{gathered} r \alpha \sqrt{\frac{1}{M}} \\ \frac{r_1}{r_2}=\sqrt{\frac{M_2}{M_1}} \\ \frac{r_1}{r_2}=\sqrt{\frac{44}{32}}=1.17 \end{gathered}$$