Question

$CO$ form a volatile compound with: -
A.Nickel
B.Copper
C.Sodium
D.Aluminium

Answer 1

Mond process is used for the extraction of nickel. In this nickel forms an intermediate and volatile compound which also dissociates easily to give pure nickel. Nickel usually comes with a lot of impurities in its ore so needs to be cleaned before using for further purposes.

Complete answer:
Mond process is used for the purification of nickel. The Mond process involves three reaction stages for completion.
Nickel usually comes with a lot of impurities in its ore so needs to be cleaned before using for further purposes. In the first step, nickel is replaced with syngas, which is a combination of hydrogen gas and carbon monoxide gas. The impure nickel oxide and other impurities react with hydrogen to form impure solid nickel.
Carbon monoxide later on reacts with the impure nickel metal. Now nickel is a block element which exists generally in the $+ 2$ oxidation state. Here in its last orbital the s and p orbitals are completely empty and as the nickel is large and $CO$ is a very strong ligand. $CO$ attacks at the s and p orbitals and occupies four orbitals, resulting in the formation of a volatile compound named $Ni{(CO)_4}(g)$. This a gaseous compound and very volatile which very easily dissociates and gives out the pure nickel.
$CO$ forms a volatile compound with nickel. The volatile compound formed is called $Ni{(CO)_4}(g)$ and the process is called Mond’s Process.

Note:
Nickel is used in the production of alloying elements, coats, batteries. It is also used in kitchen articles. Mobile phones, etc. nickel is the main cause of ferronickel production in stainless steel.