If x gram of gas is adsorbed by m gram of adsorbent at pressure P, the plot of log x/m versus log P is linear. The slope of the plot is: (n and k are constants and n > I )

According to Freundlich adsorption isotherm
$\begin{array}{l}\frac{\mathrm{x}}{\mathrm{m}}={\mathrm{kP}}^{\frac{1}{\mathrm{n}}}\\ {\log }_{10}\frac{\mathrm{x}}{\mathrm{m}}=\frac{1}{\mathrm{n}}{\log }_{10}\mathrm{P}+{\log }_{10}\mathrm{k}\end{array}$
This is the equation of straight line of type y = mx + c
Hence slope is l/n (m) and intercept is log₁₀k.