Question

What happens when phthalic anhydride is heated in evaporating dish?

Answer 1

Practically Phthalic Anhydride is considered as a very hazardous chemical. It reacts very instantly with water to form pthalic acid. If not protected, then over exposure to Phthalic Anhydride can be dangerous. The compound is very much in use in the plastic industry.

Within short term exposure you may also experience Eye and skin irritation, respiratory problems or even skin damage. Over exposure or prolonged exposure can also lead to rheumatic conditions, bronchitis, conjunctivitis etc.

When heated openly in evaporating dish it will soon react with the atmospheric Oxygen to trigger the Oxidation reaction. It has a very low melting point of 64 Deg. F. and the moment it starts to melt it forms a corrosive solution.

Answer 2

2C8H4O3 + 15O2 --------> 16CO2 + 4H2O
It's the oxidation and combustion reaction