Acetic acid reacts with barium hydroxide
Acetic acid, a weak acid, mild in nature, partially ionized in water. Barium hydroxide, a strong base, is fully ionized in water, and its ions are active. When the two meet, they will react.

Acetic acid ($CH_3COOH $), although it is a weak acid, has the general nature of acid. Barium hydroxide ($Ba (OH) _2 $), strong base, containing barium ions ($Ba ^ {2 +} $) and hydroxide ions ($OH ^ - $）。

When acetic acid meets barium hydroxide, the hydrogen ion of acetic acid ($H ^ + $, although a small amount of ionization) combines with the hydroxide ion of barium hydroxide ($OH ^ - $) to form a water molecule ($H_2O $). The chemical reaction equation is: $2CH_3COOH + Ba (OH) _2 = (CH_3COO) _2Ba + 2H_2O $.

This reaction is an acid-base neutralization reaction. Acid reacts with base, hydrogen ion combines with hydroxide ion to form water, and at the same time forms a salt. The salt produced by the reaction of acetic acid and barium hydroxide is barium acetate ($ (CH_3COO) _2Ba $). Barium acetate is soluble in water and exists in the form of ions, that is, barium ions ($Ba ^ {2 +} $) and acetate ions ($CH_3COO ^ - $）。

Experimental view, the acetic acid solution is added dropwise to the barium hydroxide solution. If the phenolphthalein test solution is dripped into the barium hydroxide solution before, it can be seen that the solution is gradually lighter from red to colorless, which is the sign of hydroxide ions being neutralized. At the same time, the solution temperature rises slightly, because the neutralization reaction is exothermic.

In summary, the reaction of acetic acid and barium hydroxide is a typical example of acid-base neutralization, which is of great significance in chemical research and practical applications.