First of all u should find out the density of all given compound .after this compare with rate of diffusion as rate of diffusion is inversely promotional to underroot of density. .
and for density you should devide the molecular weight by given volume. .

Order of increasing time required to diffuse:

1. H2 (Hydrogen gas)
2. CO2 (Carbon dioxide gas)
3. CoCl2 (Cobalt(II) chloride solution)

Explanation:

1. H2 (Hydrogen gas):
Hydrogen gas is the lightest among the three substances mentioned. It consists of diatomic molecules (H2) which are very small in size. Due to its small size and low molecular weight, hydrogen molecules can diffuse relatively quickly through a given opening. The speed of diffusion depends on the molecular weight, temperature, and pressure of the gas. Since hydrogen gas has the lowest molecular weight among the three substances, it will diffuse the fastest.

2. CO2 (Carbon dioxide gas):
Carbon dioxide gas is heavier than hydrogen gas but lighter than the Cobalt(II) chloride solution. It consists of triatomic molecules (CO2) which are larger in size compared to hydrogen molecules. The diffusion rate of carbon dioxide is slower than hydrogen due to the larger size and higher molecular weight. However, it will still diffuse faster than the Cobalt(II) chloride solution.

3. CoCl2 (Cobalt(II) chloride solution):
Cobalt(II) chloride solution is a liquid solution and has the highest molecular weight among the three substances. It is composed of Cobalt (Co) and Chloride (Cl) ions, which are much larger in size compared to gas molecules. The diffusion rate of a liquid is generally slower than that of gases due to the larger size and higher viscosity. Therefore, the Cobalt(II) chloride solution will take the longest time to diffuse through a given opening.

In summary, the order of increasing time required to diffuse through a given opening under the same conditions would be:
1. H2 (Hydrogen gas)
2. CO2 (Carbon dioxide gas)
3. CoCl2 (Cobalt(II) chloride solution)