Pure sulfuric acid is a colourless, odourless, oil-like liquid. This acid is heavier than water and its affinity for water is very high.
This acid mixes with water in any proportion and produces a lot of heat when mixed with water. Aqueous solutions of sulfuric acid conduct electricity.
After going through this post, you will get evidence for the presence of Hydrogen, Oxygen and Sulfur in Sulfuric Acid.
Evidence for the Presence of Hydrogen, Oxygen and Sulfur in Sulfuric Acid
Evidence for the Presence of Hydrogen in Sulfuric Acid
The reaction of dilute H2SO4 with zinc produces a colourless, odourless gas. If a burning wick is introduced into this gas, the wick is extinguished, but the gas burns with a bluish flame. So the gas is hydrogen. This proves that sulfuric acid contains hydrogen.
Evidence for the Presence of Oxygen in Sulfuric Acid
When concentrated H2SO4 is dropped on a red-hot rock, sulfuric acid dissociates into several gases. This gaseous mixture is then passed through a U-tube first kept in ice and then through another U-tube kept frozen. A colourless gas is emitted from the exhaust of the last U-tube.
Flameless burning jute sticks burn intensely in this gas. The gas is absorbed in an alkaline pyrogallate solution. So, the colourless gas is oxygen. This proves that sulfuric acid contains oxygen.
Evidence for the Presence of Sulphur in Sulfuric Acid
When copper scrap is mixed with concentrated sulfuric acid and heated, sulfur dioxide gas is produced. That sulfur dioxide dissolves in water to produce sulfuric acid. A yellow precipitate is obtained when the liquid is heated to 150°C in a closed glass vessel. This precipitate dissolves into carbon disulphide (CS2).
Burning the precipitate gives off the smell of burnt sulphur. So, the yellow precipitate is sulfur. This sulfur comes from sulfuric acid. So it proves that sulfuric acid contains sulfur.