Why does natural gas smell like rotten eggs?
Because the smell is added so it can be detected. If natural gas smells like rotten eggs then it contains H2S or hydrogen sulfide. Actually the smell associated with rotten eggs is hydrogen sulfide, so hydrogen sulfide does not smell like rotten eggs, rotten eggs smell like hydrogen sulfide.
If an automobile battery is in normal condition, there should be very little smell from it. The one smell that you should be aware of is the smell of rotten eggs, which indicates severe and dangerous problems with the battery. Once a battery begins to smell like rotten eggs, it cannot be saved, but must be immediately replaced. Please be aware that rotten-egg batteries can explode. Rotten-egg batteries are frequently much hotter than normal batteries…
Natural Gas itself is colorless and almost odorless - A chemical odorant (t-butyl mercaptan) is added to the Natural Gas so the leak can be detected quickly. The smell of t-Butyl Mercaptan is distinct, once you smell it you will always know it...sort of a rotten cabbage smell. Sometimes a related Chemical, Thiophane, is used...with a rotten egg smell.