Which chemical is the reason behind the brown colour of the humans faces Share with your friends Share 1 Neeraj Sunil Chandwani answered this Bilirubin Chemical 1 View Full Answer Adarsh answered this Bilirubin chemical 0 Bhumi Agarwal answered this 1) Bilirubin is the chemical reason behind the brown color of human faces. 2) sodium carbonate is commonly known as washing soda. 3) Silicon is the metal used in making microchips. Hope this helps. 0