Question

Oxidation number of N in \[{\text{HN}}{{\text{O}}_3}\] is:
A. -3.5
B. +3.5
C. -6
D. None of these.

Answer 1

Hint: In order to find the oxidation number of N, we need to use the rule 'that the sum of the oxidation number of each compound product is equal to the o if the compound is neutral or if the compound has a net charge.

Complete answer:
Let the oxidation state of N nitrogen be x.
We know that the oxidation state of H hydrogen is +1 because it is the most electropositive here and it shows -1 state only when the other elements are more electropositive.
Now, oxygen (O) has an oxidation state of -2 in 99% cases.
Since the net charge in the molecule is zero,
$1 + x + 3 \times (−2) = 0$
$\Rightarrow x = +5$

Hence D is correct.

Note: To keep track of how many electrons an atom has, chemists use oxidation numbers (or oxidation states). Oxidation numbers do not necessarily equate to actual molecular charges, so we can quantify oxidation numbers for atoms involved in the covalent (as well as ionic) bonding cycle.
Nitric acid is a strong acid having the chemical formula \[{\text{HN}}{{\text{O}}_3}\]. The spirit of nitre and aqua fortis is also known as this. This is colourless in its pure form but becomes a yellow cast as it gets older. This colour occurs as a result of the nitric acid decomposition of nitrogen and water oxides. It is highly corrosive and poisonous. It causes extreme burning in the skin. It reacts to form nitrate salts by means of hydroxides, metals, and oxides. Nitric acid is a potent oxidizing agent. It can be generated by the ammonia catalytic oxidation. This is a common reagent used in laboratories and an important chemical for the manufacture of explosives and fertilizers used in industries. Nitric acid has a pH of around 3.01.