By the 1884 definition of Svante Arrhenius (Sweden), an acid is a material that can release a proton or hydrogen ion (H +) and base, or alkali, is a material that can donate a hydroxide ion (OH-).
By the definition of both Thomas Lowry (England) and J.N. Brønsted (Denmark) working independently in 1923, an acid is a material that donates a proton and a base is a material that can accept a proton.
When an acid and a base are placed together, they react to neutralize the acid and base properties, producing a salt.
Basically, if you’ve got something that can give off H+ in water, it’s an acid. Most common acids have the letter H in the beginning of the formula, with the exception of acetic acid.
Bases, on the other hand, are compounds that give off OH- in water. if you see the formula of a base, it’s got “OH” in it. The one exception to this is ammonia, NH3.