What is the chemical formula of LPG ? Share with your friends Share 11 Purnima111 answered this combination of Propane (chemical formula C3H8) and Butane (chemical formula C4H10), 10 View Full Answer Ajay Prasad answered this C4 H1O -2 Purnima111 answered this why thumbs down. its correct 6 A................. answered this Thanks........... 4 Pooja Baruah answered this Hi, LPG is Liquefied Petroleum Gas. It is a combination of Propane (chemical formula C3H8) and Butane (chemical formula C4H10). Hope this helps. Cheers! 16