Q20 / 160 · TS EAMCET 2014 · Chemistry
The ratio of rates of diffusion of gases $X$ and $Y$ is $1: 5$ and that of $Y$ and $Z$ is $1: 6$. The ratio of rates of diffusion of $Z$ and $X$ is
- A$1: 30$
- B$1: 6$
- Correct answerC$30: 1$
- D$6: 1$
Solution
From Graham's law of diffusion
$$
\begin{aligned}
& \frac{r_X}{r_Y}=\frac{1}{5} \\
& \frac{r_Y}{r_Z}=\frac{1}{6}
\end{aligned}
$$
On multiplying Eqs. (i) and (ii),
$$
\begin{array}{rlrl}
& \frac{r_X}{r_Z}=\frac{1}{5 \times 6} & =\frac{1}{30} \\
\therefore & & \frac{r_Z}{r_X} & =\frac{30}{1} \\
\text { or } & r_Z: r_X & =30: 1
\end{array}
$$
Hence, the correct answer is option: 'C'.