No it most certainly isnt, to break all the bonds in the glycerol you need to put in an enthalpy of +6974 and the energy released when the bonds reform is -5852, so you get less energy out then you put in so it wont burn.
People often wear a ring on their index finger to demonstrate assertiveness, or power. The Middle Finger - The Meaning of the Middle Finger for Rings: Identity & Materialism - Being the tallest finger, the middle finger is associated with our purpose in life.
In Western countries yes it means the person is single. It could be a parent or relative or the person bought the ring themselves and it's for show so it goes on the middle finger or sometimes people wear 'pinkie rings' on their little finger.