Answer the question on the basis of the passage given below:

Adsorption is a surface phenomenon and it differs from absorption which occurs throughout the body of the substance which absorbs. In physisorption, the attractive forces are mainly van der Waal forces while in chemisorption actual bonding occurs between the particles of adsorbent and adsorbed more easily on the surface of a solid as compared to the gases which are liquified with difficulty. Adsorption increases with increase in pressure and decreases as the temperature is increased.

The ease with which the gas \(H_2,\, \ CH_4,\, \ CO_2\) and \(NH_3\) are adsorbed on the surface of charcoal is

\(NH_3 > CO_2 > CH_4 > H_2\)

The correct answer is option 4. \(NH_3 > CO_2 > CH_4 > H_2\).

The ease with which gases are adsorbed on the surface of charcoal or any adsorbent depends on various factors, including the nature of the gas molecules, the adsorbent surface, and the forces of attraction involved. In general, the order of ease of adsorption can be influenced by factors such as molecular size, polarity, and the strength of van der Waals forces.

The correct order, as per your correction, is \(NH_3 > CO_2 > CH_4 > H_2\). Let's discuss the factors contributing to this order:

1. Ammonia (\(NH_3\)):  Ammonia is a relatively larger molecule with a polar nature due to the presence of a lone pair on nitrogen. The polar nature of ammonia allows for stronger interactions, including dipole-dipole and van der Waals forces, which enhance its adsorption on the charcoal surface.

2. Carbon Dioxide (\(CO_2\)): Carbon dioxide is a linear molecule with polar covalent bonds. While it is larger than hydrogen, it is smaller than ammonia. The polar nature of \(CO_2\) allows for some interaction with the adsorbent surface.

3. Methane (\(CH_4\)): Methane is a small, nonpolar molecule. Its smaller size and lack of significant polarity result in weaker van der Waals forces compared to \(NH_3\) and \(CO_2\).

4. Hydrogen (\(H_2\)):  Hydrogen is the smallest molecule among the four and is nonpolar. Its size and lack of significant polarity contribute to the weakest van der Waals forces, making it the least easily adsorbed.

In summary, the order \(NH_3 > CO_2 > CH_4 > H_2\) suggests that the larger and more polar molecules (\(NH_3\) and \(CO_2\)) experience stronger interactions with the adsorbent surface, leading to greater ease of adsorption. Meanwhile, the smaller and nonpolar molecules (\(CH_4\) and \(H_2\)) exhibit weaker interactions and are less easily adsorbed on the surface of charcoal.