Question

The I.U.P.A.C name for ${K_3}[Co{(N{O_2})_6}]$ is:
(A) Potassium(I) hexanitrocobaltate(II)
(B) Potassium(I) hexanitrocobaltate(IV)
(C) Potassium hexanitrocobaltate (O)
(D) Potassium hexanitrocobaltate(III)

Answer 1

In order to answer this question, first we will mention the correct IUPAC name for the given complex compound ${K_3}[Co{(N{O_2})_6}]$ and then we will discuss few properties of it and we will also mention reaction of it.

Complete answer:
The I.U.P.A.C name for ${K_3}[Co{(N{O_2})_6}]$ is Potassium hexanitrocobaltate(III).
In this complex compound, there are six $N{O_2}^ -$ so they are named as hexanitrito. The complex has -3 charge, so the name of the central metal atom ends with $- ate$ followed by the charge in roman letters.
Potassium hexanitritocobaltate(III), is a salt with the formula ${K_3}[Co{(N{O_2})_6}]$ . It is a yellow solid that is insoluble in water. The substance is used as a yellow pigment.
Potassium hexanitrocobaltate(III) react with nitric acid:
$3{K_3}\left[ {Co{{\left( {N{O_2}} \right)}_6}} \right] + 2HN{O_3} \to 5NO + 9KN{O_2} + 3Co{\left( {N{O_3}} \right)_2} + {H_2}O$
Nitric oxide, potassium nitrite, nitrate cobalt (II), and water are produced when potassium hexanitrocobaltate (III) reacts with nitric acid. Nitric acid in a concentrated form. In a boiling solution, the reaction takes place.
Hence, the correct option is (D) Potassium hexanitrocobaltate(III).

Note:
As a yellow solid, the potassium and ammonium salts precipitate. The goal is to make sodium hexanitrocobaltate (III) out of potassium-free sodium nitrite, cobalt nitrate hexahydrate, $50\%$ acetic acid, and $95\%$ ethanol. The nitrite ions serve as both an oxidant and a ligand in this experiment.