Order of Capability to Get Adsorbed:
1. SO2
2. CH4
3. H2

Explanation:

Adsorption:
Adsorption is the process of attracting and retaining molecules or ions on the surface of a solid substance. The adsorbate (molecules/ions) adheres to the surface of the adsorbent (solid substance) due to weak intermolecular forces such as van der Waals forces.

Factors Affecting Adsorption:
Several factors influence the adsorption process, including temperature, pressure, nature of the adsorbate, and surface area of the adsorbent.

Critical Temperature:
Critical temperature is the highest temperature at which a substance can exist as a liquid. Above this temperature, the substance will exist as a gas, regardless of the pressure.

Relationship between Critical Temperature and Adsorption:
The critical temperature of a substance provides an indication of its intermolecular forces. Substances with higher critical temperatures tend to have stronger intermolecular forces, making them more likely to be adsorbed onto the surface of an adsorbent.

Order of Capability to Get Adsorbed:
Based on the critical temperatures provided, we can arrange the substances in decreasing order of their capability to get adsorbed as follows:

1. SO2 (Critical Temperature: 430 K)
- SO2 has the highest critical temperature among the three substances.
- This indicates that SO2 has stronger intermolecular forces compared to CH4 and H2.
- The stronger intermolecular forces make SO2 more likely to be adsorbed onto the surface of an adsorbent.

2. CH4 (Critical Temperature: 190 K)
- CH4 has an intermediate critical temperature.
- Its intermolecular forces are weaker than SO2 but stronger than H2.
- CH4 is less likely to be adsorbed compared to SO2 but more likely than H2.

3. H2 (Critical Temperature: 33 K)
- H2 has the lowest critical temperature among the three substances.
- This indicates that H2 has the weakest intermolecular forces.
- H2 is the least likely to be adsorbed onto the surface of an adsorbent compared to SO2 and CH4.

Conclusion:
In conclusion, the order of capability to get adsorbed in decreasing order is SO2 > CH4 > H2. This is based on the critical temperatures of the substances, which reflect the strength of their intermolecular forces. The substance with the highest critical temperature (SO2) has the strongest intermolecular forces and is the most likely to be adsorbed. Conversely, the substance with the lowest critical temperature (H2) has the weakest intermolecular forces and is the least likely to be adsorbed.