Surface Chemistry - Result Question 17
####17. Adsorption of a gas follows Freundlich adsorption isotherm. In the given plot, $x$ is the mass of the gas adsorbed on mass $m$ of the adsorbent at pressure $p \cdot \frac{x}{m}$ is proportional to
(2019 Main, 9 Jan I)
(a) $p^{2}$
(b) $p^{1 / 4}$
(c) $p^{1 / 2}$
(d) $p$
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Answer:
Correct Answer: 17. (d)
Solution:
- According to Freundlich adsorption isotherm,
$$ \frac{x}{m} \propto p^{1 / n} \Rightarrow \frac{x}{m}=K p^{1 / n} $$
On taking $\log$ on both sides, we get
$$ \log \left(\frac{x}{m}\right)=\log K+\frac{1}{n} \log p $$
On comparing with equation of straight line, $y=m x+c$, plot of $\log \frac{x}{m} v _s \log p$ gives,
$$ \begin{array}{lc} & \text { Slope } \frac{\left(y _2-y _1\right)}{\left(x _2-x _1\right)}=\frac{1}{n} \Rightarrow \frac{2}{4}=\frac{1}{2} \ \therefore & \frac{x}{m} \propto p^{1 / 2} \end{array} $$
