Question

Metal which does not form amalgam is ______
A.$Zn$
B.$Ag$
C.$Cu$
D.$Fe$

Answer 1

An amalgam is an alloy of mercury with another metal. It's going to be a liquid, a soft paste or a solid, depending upon the proportion of mercury. These alloys are formed through metallic bonding, with the electrostatic attraction of the conduction electrons working to bind all the charged metal ions together into a space lattice structure.

Complete step by step answer:
In the process of amalgam formation, the metal ion is first reduced to a metal atom. Now, this metal atom will then be solvated by a mercury atom to make an amalgam. So the Mercury needs to solvate iron atoms by incorporating the iron lattice which is extremely difficult to occur because the iron is extremely stable. This stability of the iron is because of its electronic configuration which doesn't afford the transition metal Hg to make amalgam with iron.
Amalgamation process is a method to extract gold and silver from ores. The ore is crushed and treated with mercury, in which the metal eventually dissolves. The amalgam is heated and the mercury then evaporates, leaving pure gold or silver. The process has been criticized as an environmental and occupational threat because of the extreme toxicity of mercury.
And hence Option D is the correct answer.

Note: The majority of the metals form amalgams with mercury but there are some exceptions, the notable exceptions being iron, platinum, tungsten, and tantalum. Silver-mercury amalgams are vital in dentistry, and gold-mercury amalgam is widely utilized in the extraction of gold from ore. Dentistry has often used alloys of mercury with metals like silver, copper, indium, tin and zinc. The ore consisting of the precious metals should be ground fine enough to allow the maximum exposure of the gold or silver surface to the mercury .Often, water is used as an ore is mixed with water to help disperse the ore and to promote a better precious metal to mercury interface.