Question

An aqueous solution of aluminum sulfate would show
A.Acidic
B.Neutral
C.Basic
D.Both A and B

Answer 1

Hint:Aluminum sulfate is a salt formed by the neutralization reaction between sulphuric acid and aluminum hydroxide. The neutralization reaction occurs when an acid and base react to form water and salt and involves a combination of hydrogen and hydroxyl ions to generate water. The strength of the corresponding acid and base of the salt formed tell us about the nature of the salt.

Complete step by step solution:
i.Acidic salts form from the neutralization of a strong acid and a weak base.
Example: $N{H_3} + HCl \to N{H_4}Cl$
Here $N{H_3}$ is a weak base and $HCl$ is a strong acid thus forming an acidic salt ammonium chloride.
ii.Basic salts form from the neutralization of a strong base and a weak acid
Example: $NaOH + C{H_3}COOH \to C{H_3}COONa + {H_2}O$
Here $NaOH$ Is a strong base and acetic acid is a weak acid thus forming a basic salt
iii.Neutral salts form from the neutralization of a strong acid and a strong base or weak acid and weak base.
Example: $NaOH + HCl \to NaCl + {H_2}O$
In this question, we are given the salt aluminium sulphate the formula for which is $A{l_2}{(S{O_4})_3}$
The salt aluminium sulphate is formed from the neutralization reaction between the strong sulphuric acid and the weak base of aluminium hydroxide $Al{\left( {OH} \right)_3}$.
The reaction goes as follows: ${H_2}S{O_4} + Al{\left( {OH} \right)_3} \to A{l_2}{(S{O_4})_3} + {H_2}O$
Thus aluminium sulphate is an acidic salt.
The correct answer is option A.

Note:
When a strong acid completely neutralizes a strong base, the pH of a solution is equal to $7$.When a strong base completely neutralizes a weak acid, pH of a solution is greater than $7$.When a strong acid completely neutralizes a weak base, pH of a solution is less than $7$.