Question

If we take 100m/l of water how many prectange of methane disolve in water ?

Answer 1

The solubility of gases in water depend on the atmospheric pressure and the ambient temperature.
Here's a link to the solubility of various gases (in g/1000g water).
http://www.engineeringtoolbox.com/gases-solubility-water-d_1148.html