Question

Which of the following processes represents the extraction of pure metal from its ore?

• A. Calcination
• B. Roasting
• C. Electrolytic Refining
• D. Smelting

Hint:

Remember the sequence: \[ \text{Ore} \rightarrow \text{Concentration} \rightarrow \text{Calcination/Roasting} \rightarrow \text{Reduction} \rightarrow \text{Refining} \] Only the refining step is intended to produce highly pure metal.

Answer 1

The Correct Option is C

Step 1: Understand the question.
We must choose the process that gives a pure metal from an impure one. Some choices only treat the ore, not the final metal.

Step 2: Look at calcination.
Calcination heats a carbonate ore in little air to give the oxide. It treats the ore, not the impure metal. So it is not the answer.

Step 3: Look at roasting.
Roasting heats a sulphide ore in plenty of air to give the oxide. Again this is an ore step, not a purifying step for the metal.

Step 4: Look at smelting.
Smelting reduces the oxide to crude metal using heat and a reducing agent. It gives impure metal, not pure metal.

Step 5: Look at electrolytic refining.
Here the impure metal is the anode and a thin pure sheet is the cathode. On passing current, pure metal moves onto the cathode and the impurities fall away. This gives a very pure metal.

Step 6: Choose the right process.
Only electrolytic refining turns an impure metal into a pure metal.

Step 7: State the final answer.
The process for getting pure metal is:
\[ \boxed{\text{Electrolytic Refining}} \]