Why is the aqueous solution of Aluminium Chloride acidic?
VerifiedHint: Write the balanced reaction and use the nature of the products to deduce an answer.
Complete step-by-step answer:
The reaction between Aluminum Chloride and water yields Aluminium Hydroxide and Hydrochloric Acid.
The reaction is shown below-
$AlCl_{3} + 3H_{2}O \to Al(OH)_{3} \downarrow + 3HCl$
We know that $Al(OH)_{3}$ is a weak base which means it partially dissociates in the solution and also it is sparingly soluble in water and hence it precipitates whereas HCl is a strong acid and it almost completely dissociates into $H^{+}$ and $Cl^{-}$ ions.
Now since the solution contains a strong acid and weak base, it will clearly be slightly acidic in nature.
Note: Such problems can only be solved when the behaviour of the reactants and the products is known. Writing a balanced equation gives a clearer picture. One should also know what are strong and weak acids/bases and their characteristics.
