Relative acidity of aqueous LiF, SnCl2, and YCl3 Which one of the following salts make the highest and lowest pH when dissolved in water?
$$\ce{LiF, SnCl2, YCl3}$$

My approach was :
considering the corresponding aqua acids, the order of acidity should be $\ce{Li(H2O)_n+ &lt; Sn(H2O)_n^2+ &lt; Y(H2O)_n^3+}$ and $\ce{F-}$ is less stable than $\ce{Cl-}$. So $\ce{LiF}$ is the weakest acid and $\ce{YCl3}$ the strongest.

But considering aqua acid looks weird (do they exist?) and I cannot be sure this of solution. I don't even know the right answer. Can anyone give some help?
Salt solutions are acidic because of hydrolysis.

LiF is obviously neutral, because it's a salt of very strong acid and very strong base.

Ironically, Wikipedia is wrong about Sn2+: it's much more acidic in water than Ca2+ or Zn2+, and more acidic than Y3+, 
because Sn2+ forms very stable and non-soluble hydroxo compounds and hence readily undergoes hydrolysis.

The answer is: LiF &lt; YCl3 &lt; SnCl2

Table data:

YCl3 has pH 4.5-5.8 (source),
SnCl2 has pH 1-2 (source 1, 2).