Which of the following is not a characteristic of chemisorption?

The critical temperatures of gases $A, B, C,$ and $D$ are $190 \ K, 630 \ K, 261 \ K,$ and $400 \ K$ respectively. The quantity of gas adsorbed per gram of charcoal at the same pressure is least for the gas:

Which of the following relationships is correct regarding the Freundlich adsorption isotherm?
$(1)$ $x/m = \text{constant}$ (at high pressure)
$(2)$ $x/m = k \cdot P^{1/n}$ (at intermediate pressure)
$(3)$ $x/m = k \cdot P$ (at low pressure)

What is the difference between adsorbent and adsorbate?

Which of the following is true in respect of chemical adsorption?

Why does physical adsorption decrease with an increase in temperature?