Water is made up of two elements, hydrogen and oxygen. Water is a liquid, whereas hydrogen and oxygen are gases. Hydrogen catches fire easily. Oxygen helps in burning. Water is used to put off the fire.

From the above information, answer the following questions.

a) What are the elements present in water?

b) In which state do these elements exist?

c) Write the property of hydrogen.

d) Write the property of oxygen.

e) Do the properties of water differ from hydrogen and oxygen?

a) Water is made up of two elements i.e. hydrogen & oxygen.

Water is a compound of two hydrogen atoms and one oxygen atom in the ratio 2:1 by volume.

2H₂ + O₂→ 2H₂O

b) Hydrogen & oxygen exists in gases state.

Hydrogen & oxygen exists in gases state at standard temperature and pressure. This is because the intermolecular forces of attraction between the particles are weak.

c) Hydrogen is colourless, odourless gas and it is lighter than air. It is highly flammable it readily catches fire.

d) Oxygen is colourless, odourless & tasteless gas. Oxygen is not flammable; it makes other things ignite at low temperature. But oxygen itself does not catch fire.

e) Yes, the properties of water are different from its constituent particles, i.e. hydrogen & oxygen.

Water is made up of two elements hydrogen & oxygen and is called a compound. Usually the properties of compounds are different from the properties of their constituent elements. Water exists in a liquid state & it acts as a fire extinguisher whereas hydrogen is highly inflammable gas and oxygen supports combustion.