Correct Answer – 3
Hydrocholoric acid, `HCl(aq.)`, is called “stomach acid” because it is the main acid `(~ 0.10 M)` in our digestive juices. Note that digestive juice is the acidic fluid secreted by glands in the lining of the stomach. When the concentration of `HCl` is too high in humans, problems result. These problem may range from “heartburn” to ulcers that can eat through the lining of the stomach wall.
Snakes have very high concentrations of HCl in their digestive juices so that they can digest whole small animals and bbirds
Automobile batteries contain `40% H_(2)SO_(4)` by mass. When the battery has “ran down” the concentration of `H_(2)SO_(4)` is significantly lower than `40%`. A technician checks an automobile battery by drawing some acid into a hydrometer, which indicates the density of the solution. This density is related to the concentration of `H_(2)SO_(4)`.
Oxalic acid `(COOH)_(2)` is used to remove rust and some ink stains from fabrics.