Question

In the graph of Freundlich isotherm which parameter is present by the slope of line?

Answer 1

Freundlich isotherm:

1. The Freundlich adsorption isotherm establishes an empirical relationship between the amount of gas adsorbed by a unit mass of solid (adsorbent) and the pressure at a given temperature.
2. The Freundlich adsorption isotherm is a mathematical representation of the variation of adsorption $\left(\frac{\mathrm{x}}{\mathrm{m}}\right)$ with pressure at a given temperature$\left(\mathrm{P}\right)$. The adsorbent has a mass of m, while the adsorbate has a mass of x.
3. $\frac{\mathrm{x}}{\mathrm{m}}=\mathrm{k}\times {\mathrm{P}}^{\frac{1}{\mathrm{n}}}$ Taking log on both the sides we get, $\log \frac{\mathrm{x}}{\mathrm{m}}=\mathrm{logk}+\frac{1}{\mathrm{n}}\mathrm{logP}$
4. The value of 1/n is given by the slope of the straight line, whereas the value of log k is given by the intercept on the y-axis.
5. 
6. When$\frac{1}{\mathrm{n}}=0$, $\frac{\mathrm{x}}{\mathrm{m}}$is constant, adsorption is pressure independent. and Adsorption is exactly proportional to pressure when$\frac{1}{\mathrm{n}}=1$ $\frac{\mathrm{x}}{\mathrm{m}}=\mathrm{kP}$i.e.$\frac{\mathrm{x}}{\mathrm{m}}\propto \mathrm{P}$.

Therefore, the value of $\frac{1}{\mathrm{n}}$is given by the slope of the line in the Freundlich isotherm.