Why are powdered substances more effective adsorbents than their crystalline forms?

Which of the following gases is adsorbed to maximum extent?

Which of the following statements is incorrect regarding physical adsorption?

Amongst the following statements regarding adsorption,those that are valid are :
$(a)$ $\Delta H$ becomes less negative as adsorption proceeds.
$(b)$ On a given adsorbent,ammonia is adsorbed more than nitrogen gas.
$(c)$ On adsorption,the residual force acting along the surface of the adsorbent increases.
$(d)$ With increase in temperature,the equilibrium concentration of adsorbate increases.

Write any two characteristics of chemisorption.

Which of the following statements is correct for chemisorption?