[megh44]

how do i know if a molecule is soluble in water or not??
&
if i have H2(g) + Cl2(g) = 2HCl(g)
and if Na(aq) is added to the system...will the equilibrium move to right, left, or no effect...i think its no effect because there is no Na in the equation?

thanks!

[enahs]

How are you going to add aqueous sodium ions into gases?

You know if it is soluble in water through experience, and learning your basic solubility rules in your book or what your teachers want you to know.

You can also follow the general rule like dissolves like.

Polar compounds dissolve in polar solvents, non-polar compounds dissolve in non-polar solvents. Which is water? There are many exceptions to this rule, but it is a great 'rule' -guide- for you to know.