Question

how do i tell if something can dissolve into another

the question is which f these solvents will dissolve salt, NaCl?

Answer 1

There is no easy way to tell. For an educated guess we go with "like dissolves like" which simply means that ionic compounds will dissolve in polar solvents (H2O for example) and non-polar molecules will dissolve in non-polar solvents. We can be relatively certain that NaCl will be quite soluble in water but it also dissolves, at least to some extent, in a number of other solvents, also. Scroll about half way down the page of the following web site for a list of solvents and the solubility of NaCl in them.
http://en.wikipedia.org/wiki/Sodium_chloride