Question

why nitric oxide becomes brown when released in air ?

Answer 1

Nitric oxide combines with oxygen when exposed to air to give nitrogen dioxide which is brown in colour.

Answer 2

Nitric oxide reacts with oxygen to form Nitrogen dioxide which is brown in colour.

Nitric oxide is highly reactive.Hence it reacts with oxygen when exposed to air.

2NO + O2 ------------> 2NO2.


                                     Hope it helps.................