Question

The method which cannot be used for the preparation of copper salts is:

• A. 1 (Action of acid on bases)
• B. 2 (Action of acid on carbonates)
• C. 3 (Action of acid on metals)
• D. 4 (Action of acid on sulphites)

Hint:

To make Copper(II) Sulphate in a lab, we typically react Copper(II) Oxide with hot dilute Sulphuric acid.

Answer 1

The Correct Option is C

Step 1: Understanding Salt Preparation: 
Soluble salts can be made by reacting an acid with a metal, base, or carbonate. However, the "Metal + Acid" method only works for metals more reactive than hydrogen. 

Step 2: Checking Copper's Reactivity: 
As established in question (vii), Copper is below hydrogen in the reactivity series. This means it cannot displace hydrogen from dilute acids like (HCl) or (H_2SO_4). 

Step 3: Evaluating Alternatives: 
Copper salts can be prepared by reacting Copper oxide (a base) or Copper carbonate with dilute acids, as these are neutralization/decomposition reactions that do not require hydrogen displacement. 

Step 4: Final Answer: 
Method 3 (Action of dilute acid on metals) cannot be used for copper.