Question

What is distilled water? What are its composition? Explain in detail.

Answer 1

Distilled water is water purified by boiling the water and collecting the steam. The steam is recovered by condensing the cleaner water vapor into a fresh container. The distillation process removes most impurities, so it is an effective method of water .

Answer 2

Distilled water is water that has many of its impurities removed through distillation. Distillation involves boiling the water and then condensing the steam into a clean container.
it's a compound....elements are the simplest form...like hydrogen and oxygen...seperately....if water were a mixture...you would be able to seperate the hydrogen from the oxygen easily
Distilled water has only trace amounts of materials that may come from the still itself. Both tap water and distilled water will have some dissolved gases. 

Any gas in the air, which is in contact with the water, can be dissolved in the water, although, most gases in the air aren't all that soluble in water. 

The two most important gases which are found in water are carbon dioxide and oxygen. 

Of the gases in air, CO2 is the most soluble in water, which is why both natural water and distilled water are slightly acidic. 
CO2 + H2O <==> H+ + HCO3- 

Oxygen is slightly soluble in water, enough so that fish and other aquatic life can extract enough to stay alive