Question

Why does chlorine water lose its yellow colour on standing?

Answer 1

Chlorine dissolves in water to give a strongly smelling, yellow solution called chlorine water. Chlorine water loses its yellow colour on standing in sunlight, due to the formation of a mixture of hydrochloric acid and hypochlorous acid.

Answer 2

Hey !!

Chlorine water is yellow due to the presence of ''hypochlorous'' acid (HCIO) in it. On standing, HClO being unstable, decomposes to form HCl. As a result, yellow colour disappears.

                     Cl₂ + H₂O -------> HCl + HCIO ----->  2 HCl + [O]

                                                          (Yellow)     (Colourless)

GOOD LUCK !!