Question

What happens when hydrogen burns in air?

Answer 1

Hint:. Hydrogen reacts with mainly one component of air i.e. oxygen. We know that oxygen in its molecular state is used as an oxidizing agent. So write the oxidation product of hydrogen molecules to answer the above question.

Complete step by step solution:
Air present around us contains mainly the gases, nitrogen, oxygen and argon. 20.8% of the atmosphere consists of oxygen.
Hydrogen when brought to flame or burnt, it reacts with the oxygen present in the air to form the compound water.
The chemical reaction between hydrogen and oxygen is given below:
$\text{2}{{\text{H}}_{\text{2}}}\text{ + }{{\text{O}}_{\text{2}}}\text{ }\to \text{ 2}{{\text{H}}_{\text{2}}}\text{O}$
Therefore, we can conclude that when hydrogen burns in air, a chemical reaction takes place leading to the formation of the compound water.

Additional information:
Water is a polar inorganic compound that is tasteless, odourless and almost colourless at room temperature. Water is considered as the universal solvent as many solutes readily dissolve in water. It is the most abundant substance of earth.
Water exists as a liquid because there is strong hydrogen bonding between the water molecules due to the high electronegativity of oxygen atoms.
However, the extent of hydrogen bonding starts reducing as we move down the group. In fact, the very next hydride, hydrogen sulphide exists as a gas. This is because the electronegativity is lesser than oxygen and thus the hydrogen bond formed is very weak.

Note: It is important to know that although water is formed as a product of the above chemical reaction, the state of water is not liquid. This is because the energy released during the chemical reaction increases the temperature beyond the boiling point of water and thus product formed is in gaseous state i.e. water vapour.