(a) Indigestion: Sometimes, the stomach produces too much hydrochloric acid, called hyperacidity, which causes indigestion. The acid is neutralised by taking a tablet (antacids) containing calcium carbonate, aluminium or sodium hydrogen carbonate.
(b) Ant sting: When you are stung by an ant, the burning sensation on your skin is caused by methanoic acid. You can neutralise the acid by rubbing a dock leaf on the wound. As you press the dock leaf against the wound, a base in the leaf juices reacts with the acid in the sting and neutralises it so that the burning sensation stops.
