The Freundlich adsorption isotherm is given by: $$ \frac{x}{m} = kp^{1/n} $$ where $x$ is the mass of adsorbate, $m$ is the mass of adsorbent, $p$ is the pressure, $k$ is a constant, and $n$ is another constant. We are given that the slope (1/n) is unity (1), and $k = 0.1$. We want to find $x/m$ at $p=2$ atm. $$ \frac{x}{m} = (0.1)(2^1) = 0.2 $$