Question

There are following extraction process of silver but not:
A.as a side product in electrolytic refining of copper
B.Parke's process in which Zn is used to extract silver by solvent-extraction from molten lead
C.by the reaction of silver sulphide with KCN and then the reaction of a soluble complex with Zn.
D.by heating $Na[Ag{\left( {CN} \right)_2}]$

Answer 1

To answer this question the concepts in metallurgy should be known. Metallurgy is a process that is used for the extraction of metals to obtain them in their pure form. The compounds of metals mixed with rocks, soil, sand, and impurities are referred to as minerals. These minerals are called ores.

Complete step by step answer:
Parke ‘s process is a process to remove silver from the lead.
By electrolysis process, the impure metal and pure metal are taken as anode and cathode respectively. A salt of that particular metal is taken as an electrolyte. When electricity is passed the impure metals get oxidized and converted into ions. On the other hand, metal ions from the solution get reduced at the cathode. In this way, metal gets purified and the impurities get separated and get collected under an anode electrode. By this process copper (Cu) metal, nickel metal lead gold, and silver get purified.
By heating, $Na[Ag{\left( {CN} \right)_2}]$ it forms a complex with the Ag, as a result, the extract of silver is not possible by heating of $Na[Ag{\left( {CN} \right)_2}]$ . The actual reactions of extraction of silver are as follows,

$$A{g_2}S + 4NaCN \to 2Na[Ag{(CN)_2}] + N{a_{2}}S\;\left( {reversible\,reaction} \right) \\\ 2Na[Ag{(CN)_2}] + Zn \to N{a_2}[Zn{(CN)_4}] + 2Ag\; \\\$$

So, the correct option is D.

Additional information:
The metallurgical process can be understood by the following points:
1.The first step is crushing and grinding of ores into a fine powder using a crusher. This is known as pulverization.
2.Impurities can be removed from the ore and this process is called ore dressing or concentration of minerals.
3.The concentration of ores is done by many methods, these are the hydrolytic method, magnetic separation, froth floatation, and roasting and calcination.

Roasting is a metallurgical process involving a gas-solid reaction in presence of air at high temperatures to purify the ore of the material.
In the case of roasting of sulfide ore done in metallurgy of copper. Due to partial roasting, the copper sulfide becomes copper oxide which further reacts with unreacted copper sulfide and gives auto reduction. The reaction is shown below.
$2C{u_2}S + 3{O_2}\; \to 2C{u_2}O + S{O_2}$ , $2C{u_2}O + C{u_2}S\; \to 6Cu + S{O_2}$ .

Note: There are some other methods by which metals can be extracted.
1.Zone refining: When the solubility of the impurities is greater in the molten state than in the solid-state of the metal, this process is used. In this process, an impure metal rod is heated by a moving heater from one end to another. When one end of the metal melts the impurities get soluble and concentrated into that melted area, and when the heater moves forward it leaves pure solidified metal behind. In this way, all impurities get collected into one end of the metal rod. By this process Zinc (Zn) metal gets purified.
2.Van Arkel method: This method is also called Vapour Phase refining. In this process, a volatile impure metal is heated. As a result, the metal gets vaporized and impurities left behind as solid. By this process titanium (Ti) metal gets purified from iodine.
3.The Mond process: In this process the impure metal reacts with CO and forms gaseous metal carbonyl. The impurities are left unreacted.by this process nickel (Ni) metal get purified