pH of solution after adding SiCl4

Why is it that adding $\ce{SiCl4}$ will cause the pH of a solution to become acidic? I thought that only salts (ionic bonds break in water) can change the pH once dissolved in water. $\ce{SiCl4}$ has covalent bonds, so why does the pH change?




Silicon is very oxophilic and $\ce{SiCl4}$ irreversibly hydrolyzes in water as follows:
$$\ce{SiCl4\_{(l)} + 4 H2O\_{(l)} -> 4 HCl\_{(aq)} + Si(OH)4\_{(s)}} $$


The release of $\ce{HCl}$ creates hydrochloric acid and lowers the pH.


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$\ce{Si(OH)4}$ exists as $\ce{SiO2.2H2O}$ called Silica Gel. $\ce{Si(OH)4}$ as such does not stand for long, probably due to overcrowding of electrons around Si atom by $\ce{4 OH-}$ groups. Hence, $\ce{Si(OH)4}$ stabilises itself as $\ce{SiO2.2H2O}$


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