Question

Water can be prepared in laboratory:
A. By burning hydrogen
B. Using Eudiometer
C. Both A and B
D. None of the above

Answer 1

Water was prepared in a laboratory by Antoine Lavoisier for the first time in 1786. He has done this experiment in his own laboratory in Paris. He was given a name as a water producer. For the preparation of water in the laboratory, we can remember the general production of water.

Complete step by step answer:
Water is a molecule which is made up of two hydrogen atoms and one oxygen atom. Thus for the preparation of water molecules, hydrogen atoms and oxygen atoms are necessary. The electrons in each atom should be bonded with each other. Thus, when hydrogen is burnt in air in the presence of oxygen, water is formed. This is an exothermic reaction since a large amount of heat is released. We need a high amount of energy for this reaction to occur. We know that hydrogen gas is flammable and oxygen is a molecule which helps in the combustion reaction. So the high amount of energy can be taken from these molecules.
The chemical equation of preparation of water is given below:
$2{{{H}}_2} + {{{O}}_2} \to 2{{{H}}_2}{{O}}$
A device in which the change in volume of gas is measured followed by a physical or chemical change is termed as a eudiometer. Water can also be prepared using an eudiometer since the water vapor is formed which is the gaseous form of water molecule.
So water can be prepared by burning oxygen and using an Eudiometer.

Hence the correct option is C.

Note: We need free hydrogen from the environment to prepare the water molecule. But free hydrogen is not much available in the environment. Hydrogen exists in combination with other elements like oxygen and carbon. It needs more energy to extract hydrogen alone from these compounds.