Question

The adsorption of gases on solids can be described by Freundlich’s equation, `x/m = kP^(1//n)`.

1. How are the values of k and n determined experimentally?
2. Explain, why should the value of n be equal to or greater than one?

Answer 1

Fig. Linear graph between `bb(log (x/m))` and log P.

Taking logarithms on both sides, we get

\[\log\left(\frac{x}{m}\right) = \log k + \frac{1}{n} \log P\]

Thus, if we plot a graph between `log (x/m)` and log P, a straight line will be obtained. The slope of the line is equal to `1/n` and the intercept is equal to log k. Thus the values of k and n are determined. n can take a value any where between 1 and a large number depending upon the pressure. At low pressure n = 1.

∴ `x/m = kP`