Question

The aqueous solution of copper sulphate has the following nature:
a.) Acidic
b.) Alkaline
c.) Amphoteric
d.) Neutral

Answer 1

Hint: Try to recall that copper sulphate is produced industrially by treating copper metal or its oxides with hot concentrated sulphuric acid and also it is known to you that cupric hydroxide is a weak base. Now by using this you can easily find the correct option from the given options. Complete answer:
It is known to you that the chemical formula of anhydrous copper sulphate is $CuS{O_4}$ and that of hydrated is $CuS{O_4}.5{H_2}O$. Also, the common name of aqueous copper sulphate is blue vitriol or roman vitriol or vitriol of copper. When copper sulphate is dissolved in water then following reaction takes place:
$CuS{O_4}(s) + 2{H_2}O \to Cu{\left( {OH} \right)_2}(l) + {H_2}S{O_4}(aq)$. Now, you can see in the above reaction that when copper sulphate salt is dissolved in water, it gets hydrolysed into cupric hydroxide which is a weak base and sulphuric acid which is a strong mineral acid. Since, cupric hydroxide is a weak base and sulphuric acid is a strong acid so, hydrogen ion is more than hydroxyl ion in water and as result of this, the aqueous solution of copper sulphate is acidic in nature.
Therefore, from above we can easily conclude that option A is the correct option to the given question.

Note: It should be remembered to you that copper sulphate salt undergoes acidic hydrolysis when dissolved in water. Also, you should remember that copper sulphate is used as herbicide in irrigation and municipal water treatment systems.