Question

phenol turns pink on exposure to air and light

Answer 1

Phenol turns pink in colour on exposure to air due to slow oxidation. Phenol gets oxidised to quinone and then quinone combines with the phenol to give an addition product known as phenoquinone which is pink in colour. 

Answer 2

Explanation:

Phenol is basically an organic compound which is aromatic in nature. Phenol has a hydroxyl group bonded with phenyl group giving it its aroma. It has the molecular formula $C_6H_5OH$. Phenol is a strong acid. It is also very toxic in nature.

On exposure to air and light, phenol undergoes oxidation. When phenol oxidizes, quinone is formed. This quinone when reacts with phenol, it combines to form phenoquinone which is pink in color.