Question

What happens when \(\text{CuSO}_4\) is dissolved in water?
Identify correct statements from the following

• A. Anion of the salt react with water.
• B. Its solution will turn red litmus into blue.
• C. The pH of the solution will be less than \(7\).
• D. The \(\text{CuSO}_4\) will not undergo hydrolysis reaction.

Hint:

CuSO4 is a salt of a weak base and a strong acid, so the solution is acidic.

Answer 1

The Correct Option is C

Step 1: Identify the salt
CuSO\(_4\) comes from the weak base Cu(OH)\(_2\) and the strong acid H\(_2\)SO\(_4\).

Step 2: Hydrolysis
Only the cation hydrolyses: \(\text{Cu}^{2+}+2\text{H}_2\text{O}\rightleftharpoons\text{Cu(OH)}_2+2\text{H}^+\).
This releases H\(^+\), so pH \(<7\).

Step 3: Check options
(A) is false, since the anion SO\(_4^{2-}\) does not react (it is the conjugate base of a strong acid).
(B) is false, an acidic solution turns blue litmus red.
(C) is true.
(D) is false, since the salt does hydrolyse.

Final Answer:
CuSO\(_4\) solution has pH below \(7\), option (C). \[ \boxed{\text{(C)}} \]