Question

Which one of the following statements about $NO$ is wrong?
(A) NO is an odd electron molecule
(B) It is a free radical and highly reactive
(C) It readily forms complexes with transition metal ions
(D) It can be prepared by heating $N{H_4}N{O_3}$ at ${250^0}C$

Answer 1

In order to answer this question, you must know the properties of Nitric Oxide,$NO$. Nitric oxide is formed from nitrogen and oxygen by the action of electric sparks or high temperatures or, more conveniently, by the action of dilute nitric acid upon copper or mercury.

Complete answer: Having an odd number of electrons in a molecule guarantees that it does not follow the octet rule, because the rule requires eight electrons (or two for hydrogen) around each atom. The most commonly encountered stable species that exist with an odd number of electrons are nitrogen oxides, such as nitric oxide $NO$ etc.
$NO$ is a stable free radical with one or more unpaired electrons. It does not obey the octet rule. It is a highly reactive molecule.

Transition elements have a tendency to form complexes more than s and p block elements. Hence, they are able to form complexes with the groups which are able to donate an electron pair. $NO$ has an unpaired electron and can therefore form complexes with transition metal ions.

NO can be made in the laboratory by reacting sodium nitrite $(NaN{O_2})$ in the presence of a reducing agent, such as $F{e^{2 + }}$in an acidic medium.
$N{H_4}N{O_3}$ at ${250^0}C$ gives ${N_2}O$ not $NO$.
And hence the statement in option D is wrong.
Therefore, Option (D) is correct.

Note:
Nitric oxide is a by-product of combustion reactions that occur in engines, like those in automobile engines and fossil fuel power plants. It is also produced naturally during the electrical discharge of lightning during thunderstorms.