Re: What impacts technology have had on changing ideas about acids/bases?

Vera,

Theories on the definition of acids and bases have developed over a long time. The Greeks were the first who tried to identify what an acid was - by using their tongues. If something was sour, it was an acid to them.

Skip forward to 1743.

Antoine Lavoisier, whose experiments you can read about here, was theorizing that an acid is only acidic because of some other item which it has in it - he called this "oxygen." (Right idea, but wrong substance). He was able to prove this because of his equipment, including a standardized crystal bowl and controlled amounts of mercury and iron. However, he still proved his idea through observation and experimentation. Different metals took different amounts of 'oxygen' to show the same effect, and he noted this visually.

Humphrey Davy, of Britain, extended Lavoisier's ideas by confirming that oxygen was not responsible for acidity. However, he did not prove how.

Justus Liebig, of Germany, was able to identify Lavoisier's 'oxygen' as hydrogen. He did this with a new device he invented - the Kaliapparat. Because of his equipment, he could easily figure out the amount of hydrogen in a substance. This allowed him to correct Lavoisier's idea.

Also, you could say that bases were just invented as the contrast to acids. All the scientists were excited about acids, and later created bases as the opposite of an acid.

Hopefully, by now you can see that the earliest scientists worked by using their empirical abilities - their own observations or tools. That's why different ideas came forth in the late 1880s when the atomic theory was proposed.

Svante Arrhenius, of Sweden, was able to prove in 1884 that acids are compounds which form H3O+ ions in water, while bases produce OH-. He was only able to see this because of the advancements of atomic theory.

The previous scientists thought of compounds in whole terms instead of in terms of molecules and atoms. Arrhenius took this new theory of atoms and could see where acids and bases came from.

The main determining factors in acid-base theory were technology and atomic theory. As you can see, the scientists from before the 1800s had a completely different mindset about chemistry. The atomic theory changed every scientist's outlook and gave all the ability to think of reactions in terms of basic units rather than inseparable blocks. This of course was supplemented by newer technology which made it easier to prove these theories.

Hope that didn't confuse you too much...

Here are the websites which I used for this answer. BBC, ChemTeam, Lavoisier's Experiments, Liebig, Arrhenius, Atomic Theory

Hope that helps,
Adil B.