5. Gain and Loss of Electrons   Previous PageNext Page
       Acid-Base Neutralization and Salts

We can regard a salt as the result of the neutralization of an acid and a base. An acid dissolved in water releases hydrogen ions:

and a base dissolved in water produces hydroxide ions:

(Remember that all ions in aqueous solution are hydrated, or surrounded by water molecules, even though this usually is not written explicitly.) If we mix an acid and a base, a reaction occurs by the combination of and ions into water molecules:

(Only a small percentage of the H-F molecules in solution will be dissociated into and ions initially, therefore HF is called a weak acid. As the above reaction occurs, however, more HF will dissociate.)


The real reaction is the combination of hydrogen and hydroxide ions; the other ions only go along for the ride:

If the number of and ions is the same, the final solution is neutral. The reaction of an acid with a base in general is called neutralization, and represents the "canceling out" of the acidic and basic properties of the original solutions by the elimination of and ions.

The neutralized solution shown on the next page is nothing but an aqueous solution of equal quantities of and ions. If the solution is evaporated to dryness, salt crystals of LiF are left behind. The result of acid-base neutralization is a salt and water.

In principle, a fanatic chemist could season his beefsteak by pouring over it equal quantities of lye or sodium hydroxide, NaOH, and hydrochloric acid, HCl. The result after neutralization would be common table salt, NaCl. If the chemist were very precise about quantities, and very thorough about mixing, then he might get away with such a procedure, but it is not recommended.

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