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 $\ce{Li(H2O)\_n+ < Sn(H2O)\_n^2+ < Y(H2O)\_n^3+}$ 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](https://en.wikipedia.org/wiki/Hydrolysis#Metal_aqua_ions).


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 < YCl3 < SnCl2


Table data:


YCl3 has pH 4.5-5.8 ([source](http://www.espimetals.com/index.php/msds/773-yttrium-chloride-hydrate)),  

SnCl2 has pH 1-2 (source [1](http://www.emdmillipore.com/US/en/product/Tin(II)-chloride-dihydrate,MDA_CHEM-107815), [2](http://www.ch.ntu.edu.tw/~genchem99/msds/exp10/SnCl2.pdf)).


 1

A basic salt is formed when a weak acid reacts with a strong base. $\ce{LiF}$ is formed from strong base $\ce{LiOH}$ and weak acid $\ce{HF}$ to give a basic salt.


$\ce{HF}$ is not a strong acid.


 0