Chemistry 30

1.2 Arrhenius Theory of Acids & Bases

By now you may already made a good guess as to the key "components" of acids and bases. If you look carefully at the formulas listed on the last page (Acids and Bases Section 1.1) you'll see that the acids all have one thing in common, and most of the bases another.

Although the properties of acids and bases had been recognized for a long time, it was Svante Arrhenius in the 1880's who determined that: the properties of acids were due to the presence of hydrogen ions, H+, and the properties of bases were due to the presence of hydroxide ions, OH-. This became known as the Arrhenius Theory of Acids and Bases	ACIDS hydrochloric acid, HCl sulfuric acid, H2SO4 nitric acid, HNO3 acetic acid, HC2H3O2 (vinegar) carbonic acid, H2CO3 formic acid, HCOOH acetylsalicylic acid, C6H4(OCOCH3)CO2H
BASES sodium hydroxide, NaOH potassium hydroxide, KOH magnesium hydroxide, Mg(OH)2 calcium hydroxide, Ca(OH)2 ammonia, NH3 - oops! Where's the OH-?	Scavenger Hunt Find a picture of Svante Arrhenius What was his nationality? When did he live?

 

An important aspect of that theory is that these compounds only become acid or bases when in solution. HCl, hydrogen chloride, for example is not an acid when in its gaseous phase (according to the Arrhenius Theory). Add it to water, however, and we have a very strong acid. We need to examine what happens when we add them to water that suddenly produces either acidic or basic properties.