Nitrous Acid: Overview, Questions, Preparation

The chemical formula of nitrous acid is HNO2. The total number of electrons present in nitrous acids is 18. Hydrogen has 1, nitrogen contains 5 electrons, and an oxygen molecule has 6 electrons each (12), adding up to 18 electrons. Nitrogen and oxygen both share a double bond in nitrous acid, which means that each atom has a charge of 0.

1. Nitrous acid boils at a temperature of 82°C and very acidic.
2. Nitrous acid remains unchanged when it comes in contact with heat, but when nitrous acid is mixed with water, the carbonation effect occurs with nitrous gas.
3. Nitrous acid has a bitter and unpleasant odor, and the color is pale blue.

1. For the preparation of diazonium salts from amines, nitrous acids can be used.
2. Nitrous acid can be used for the production of azo dyes in the reaction of Sandmeier.
3. In liquid-fuel rockets, nitrous acid can be used as an oxidizer.
4. Nitrous acid can help remove the toxic components from the reactions like sodium azide compound, which is explosive.

Briefly, there are two ways to decompose the nitrous acid that are explained below-

1. One of the most common ways is to decompose the nitrous acid that leaves behind water, nitric acid, and nitrogen dioxide. The chemical formula is –

                              2HNO2 NO2 +NO + H20

2. The other way to decompose the nitrous acid is when it leaves behind nitric acid, nitrous oxide, and water. The chemical formula for this type of decomposition is as follows-

                            4HNO2 2HNO3 + N2O +H2O

Nitrous Acids for Class 10

This chapter is one of the most primary concepts to understand and grasp, containing a weightage of 3-4 marks overall. This chapter includes one small objective type question and three short one-mark questions accounting for the overall marks mentioned above.

Example 1) Write the oxidation reaction of nitrous acid.

Answer – When hydrogen sulfide oxides with nitrous acid, Sulphur is formed. The chemical reaction of this oxidation as follows:

H2S + 2HNO2 2H2O + 2NO + S

Example 2) State a chemical reaction when bases and nitrous acids react together.

Answer – When nitrous acids react with bases, nitrite salts form. The chemical reaction is:

2HNO2 + NA2CO3 2NANO2 + HCO3

Example 3) Write the systematic IUPAC name of nitrous acid.

Answer  The systematic IUPAC name of nitrous acid is Hydroxidooxidonitrogen.

Q. Is nitrous acid unstable?

Q. Why is hydrochloric acid more acidic than nitric acid?

Q. Why is nitric acid used interchangeably with hydrochloric acid?

Q. Why is Nitrous acid dangerous?

Q. What is the pH level of nitrous acid?