Chemistry - Metallurgy Question with Solution | TestHub

In the cupellation process, silver is purified by oxidation of impurities like lead; silver itself remains unoxidized.

In the Mac-Arthur Forrest cyanide process, argentite is converted into the soluble complex $[Ag(CN{)}_2{]}^{-}$; silver is not oxidized.

In Parke's process, silver is separated from lead by zinc; no oxidation of silver occurs.

Silver is oxidized by concentrated HNO₃:

$$3Ag+4HN{O}_3(conc.)\to 3AgN{O}_3+NO+2H_{2}O$$

Correct Answer: (D) Reaction with concentrated HNO₃