Question

Match List-I (Metals) with List-II (Refining Methods): {ll} List - I & List - II
A. NICKEL & I. ELECTROLYTIC REFINING
B. TITANIUM & II. ZONE REFINING
C. GERMANIUM & III. VAN ARKEL METHOD
D. COPPER & IV. MOND PROCESS

• A. A-IV, B-I, C-III, D-II
• B. A-III, B-IV, C-II, D-I
• C. A-II, B-III, C-II, D-I
• D. A-IV, B-III, C-II, D-I

Hint:

To solve metallurgical matching questions instantly, remember the acronyms or classic pairings: Ni-Mond (Nickel - Mond) and Ti-Van (Titanium - Van Arkel). Securing just the Nickel to Mond Process link (\(\text{A} \rightarrow \text{IV}\)) immediately narrows down the viable choices to two options!

Answer 1

The Correct Option is D

Concept: Refining is the final step in metallurgy used to obtain high-purity metals from crude specimens. The choice of refining method depends heavily on the chemical properties of the metal and the nature of its impurities:
• Vapour Phase Refining: The crude metal is converted into a volatile compound by heating with a specific reagent, which is then decomposed at a higher temperature to yield pure metal. This includes:
• Mond Process: Used specifically for refining Nickel using carbon monoxide (\(\text{CO}\)).
• Van Arkel Method: Used for refining Titanium or Zirconium using iodine (\(\text{I}_2\)) to remove oxygen and nitrogen impurities.
• Zone Refining: Based on the principle that impurities are more soluble in the molten state (melt) than in the solid state of the metal. It is highly effective for preparing ultra-pure semiconductors.
• Electrolytic Refining: The impure metal is made the anode, while a thin strip of pure metal serves as the cathode in an electrolytic bath containing a soluble salt of the same metal.

Step 1: Matching metal A (NICKEL) with its industrial refining method.
Nickel is refined using the Mond Process. The crude metal is heated in a stream of carbon monoxide to form volatile nickel tetracarbonyl, which is subsequently decomposed at higher temperatures to yield pure nickel: \[ \text{Ni} + 4\text{CO} \xrightarrow{330-350\text{ K}} \text{Ni(CO)}_4 \xrightarrow{450-470\text{ K}} \text{Ni} + 4\text{CO} \] Thus, A matches with IV.

Step 2: Matching metal B (TITANIUM) with its high-purity extraction technique.
Titanium is purified using the Van Arkel Method. The crude metal is heated in an evacuated vessel with iodine to form volatile titanium tetraiodide, which is then electrically decomposed on a hot tungsten filament: \[ \text{Ti} + 2\text{I}_2 \xrightarrow{523\text{ K}} \text{TiI}_4 \xrightarrow{1700\text{ K}} \text{Ti} + 2\text{I}_2 \] Thus, B matches with III.

Step 3: Matching metal C (GERMANIUM) with its semiconductor-grade purification process.
Germanium, being a semiconductor required in high-purity states, is refined using Zone Refining to reduce elemental impurities down to fractional parts per million (ppm). Thus, C matches with II.

Step 4: Matching metal D (COPPER) with its standard metallurgical refining step.
Blister copper obtained from smelting is refined to upwards of 99.9% purity via Electrolytic Refining, where pure copper plates out at the cathode. Thus, D matches with I. Combining all matches together yields the configuration: A-IV, B-III, C-II, D-I, which matches option (D).