Question

Match list I with list II and select the correct answer using the codes given below the lists : List I \(\quad\) List II Cyanide Process \(\quad\) A. Ultra pure Ge I. Floatation process B. Pine oil II. Electrolytic reduction C. Extraction of \(\mathrm{Al}\) IV. Zone refining D. Extraction of \(\mathrm{Au}\) Codes: (1) I-C, II-A,III-D,IV-B (2) I-D, II-B,III-C,IV-A (3) I-C, II-B,III-D,IV-A (4) I-D, II-A,III-C,IV-B

Short answer

The correct answer is (4).

Step-by-step solution

Identify processes in List I

List I has the following processes: I. Floatation process, II. Electrolytic reduction, III. Cyanide Process, and IV. Zone refining.

Determine the associated elements or compounds in List II

List II contains: A. Ultra pure Ge, B. Pine oil, C. Extraction of Al, and D. Extraction of Au.

Match the processes with their corresponding elements or compounds

1. Floatation process is often used with Pine oil, so I goes with B.2. Electrolytic reduction is commonly used for the extraction of Al, so II goes with C.3. Cyanide process is used for the extraction of Au, so III goes with D.4. Zone refining is used for obtaining ultra pure Ge, so IV goes with A.

Select the correct code

The correct matches are:I - B, II - C, III - D, IV - A.So the correct answer is (4).

Key concepts

Cyanide Process

The Cyanide Process, also known as cyanidation, is used to extract gold from its ores. This method is highly efficient and widely used in gold mining industries.

The process involves the following steps:

• Crushing and grinding the ore to a fine powder
• Adding a cyanide solution to the powdered ore
• Allowing the cyanide to react with the gold to form a soluble complex
• Separating the gold-cyanide complex from the solid residue
• Recovering gold from the solution through precipitation or electro-winning

This method proves to be very effective but poses environmental concerns due to the toxic nature of cyanide. Therefore, proper waste management and detoxification measures are necessary.

Electrolytic Reduction

Electrolytic Reduction is a process used to extract metals from their ores using electricity. This technique is commonly employed for metals like aluminum and copper.

The process works as follows:

• An electrolyte solution containing metal ions is prepared
• An electric current is passed through the solution
• The metal ions get reduced (gain electrons) at the cathode, forming pure metal
• Impurities are either left in the solution or form on the anode

For example, in the extraction of aluminum, the ore (bauxite) is first converted to alumina, and then electrolytically reduced to form pure aluminum. The efficiency of electrolytic reduction makes it a widely used method in metallurgy.

Floatation Process

The Floatation Process is designed for the separation of minerals from their ores based on differences in their hydrophobic properties.

Here are the main steps of the floatation process:

• Crushing and grinding the ore into fine particles
• Mixing these particles with water to form a slurry
• Adding surfactants and air to create bubbles
• The desired mineral particles attach to the bubbles and float to the surface
• Skimming the mineral-laden bubbles off the surface for further processing

Pine oil is a common surfactant used in this process. The floatation method is particularly effective for sulfide ores like copper, lead, and zinc.

Zone Refining

Zone Refining is a method used to obtain ultra-pure elements, such as germanium and silicon. This process is particularly important in semiconductor manufacturing.

Here's how zone refining works:

• The impure metal is formed into a rod
• A heating coil generates a molten zone that moves along the rod
• Impurities concentrate in the molten region and move with the molten zone
• As the zone passes, the pure metal crystallizes behind it, leaving impurities in the molten phase

This technique can produce materials of extremely high purity, which is crucial for electronic components that require minimal impurities to function effectively.