Question

List I	List II
i. Cyanide process	A. Ultrapure Ge
ii. Floating process	B. Pine oil
iii. Electrolytic reduction	C. Extraction of $Al$
iv. Zone refining	D. Extraction of $Au$

Match List-I with List-II and select the correct answer using the codes given below the lists:

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

Answer 1

Answer: (B)

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

I. Cyanide Process: Silver and gold are extracted by the cyanide process (Mac Arthur - Forrest process). After the preliminary crushing and concentration by froth floatation process, the ore is leached with dilute (0.4 - 7%) solution of sodium cyanide, made alkaline by adding lime and kept agitated by a current of air. Silver (or gold) pass into solution as argentocyanide (or aurocyanide).

II. Froth Floatation Process:- The process is best suitable for sulphide ores. The process is based on different wetting characteristics of the ore and gangue particles with water and pine oil.

III. Electrolytic Reduction: Al, Cu, Ag, Mg etc are purified by this method. Pure metal is used as cathode and crude metal is used as anode. Aqueous solution of salt of the metal acts as electrolyte.

IV. Zone Refining: This method is employed to get metal of very high purity i,e. ultra pure samples of Ge Si, B,Ga,In. This method is based on the fact that impurities are more soluble than the pure metal in the melt.

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