Select the graph that correctly describes the adsorption isotherms at two temperatures $$T_1$$ and $$T_2$$ ($$T_1 > T_2$$) for a gas:
($$x$$ - mass of the gas adsorbed, $$m$$ - mass of adsorbent, $$P$$ - pressure)

Solution

Based on NCERT, the equation for pressure looks as follows:$$\frac{\ x}{m}=k.p^{\frac{\ 1}{n}}$$. The relationship is generally represented in the
form of a curve where mass of the gas adsorbed per gram of the adsorbent is plotted against pressure. These curves indicate that at a fixed pressure, there is a decrease in physical adsorption with increase in temperature. Thus, the correct answer is C.