Question

Match items of Column I with the items of Column II and assign the correct code:

• (a) $\to$ (ii) ,(b) $\to$ (iii) ,(c) $\to$ (i) ,(d) $\to$ (v)
• (a) $\to$ (i) ,(b) $\to$ (ii) ,(c) $\to$ (iii) ,(d) $\to$ (iv)
• (a) $\to$ (iii) ,(b) $\to$ (iv) ,(c) $\to$ (v) ,(d) $\to$ (i)
• (a) $\to$ (iv) ,(b) $\to$ (ii) ,(c) $\to$ (iii) ,(d) $\to$ (i)

Answer 1

The Correct Option is D

Extraction Processes 

Cyanide Process:

The cyanide process is used to extract gold (Au) from its ores. The process involves the following reactions:

\(4Au + 8NaCN + O_2 + 2H_2O \to 4Na[Au(CN)_2] + 4NaOH\)

After this, the impure gold cyanide complex is treated with zinc to reduce the gold:

\(2Na[Au(CN)_2] \xrightarrow{[Zn]} \underset{\text{ppt}}{2 Au} + Na_2[Zn(CN)_4]\)

Froth Floatation Process:

The froth flotation process is used for concentrating sulphide ores. This method involves using air bubbles to separate the desired minerals from the rest of the ore by creating froth, where the mineral particles attach to the bubbles.

Electrolytic Reduction (Hall-Heroult Process):

The Hall-Heroult process is used to extract aluminium from its ore, bauxite. This process involves the electrolytic reduction of bauxite in the presence of cryolite:

Electrolytic reduction of bauxite is done by dissolving the ore in molten cryolite (Na₃AlF₆) and applying a direct current. This reduces aluminium oxide to aluminium metal at the cathode.

Zone Refining:

Zone refining is a method of purifying semiconductor materials like Germanium (Ge) and Silicon (Si). In this method, a molten zone is passed along the material, selectively dissolving impurities into the molten region, which is then moved to the next region for further purification.

Answer 2

1. Cyanide process: This process is used for the extraction of gold (Au), hence it is matched with (iv) Extraction of Au.
2. Froth flotation process: This is used for concentrating sulphide ores like ZnS (zinc sulfide), so it is matched with (ii) Dressing of ZnS.
3. Electrolytic reduction: This is the method used to extract aluminum (Al) from bauxite, so it is matched with (iii) Extraction of Al.
4. Zone refining: This technique is used for purifying materials like germanium (Ge), so it is matched with (i) Ultrapure Ge.

Correct Code:

(a) → (iv), (b) → (ii), (c) → (iii), (d) → (i)