Question

Why is the aqueous solution of Aluminium Chloride acidic?

Answer 1

Hint: 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-

$AlC{l}_3+3H_{2}O\to Al(OH{)}_3\downarrow +3HCl$

 

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 $C{l}^{-}$ 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.