What is an acid?
An acid is a which can easily loose a .
Acids (such as the formic acid shown in figure a) often contain the COOH, where the C ( atom) has a double with one of the O ( atoms). This is shown by a double line on the diagram.
like oxygen more than they like , so there is only a thin electron around the hydrogen atom on the left.
When in the hydrogen , the p+, can therefore easily escape and wander off, causing damage in other molecules.
Meanwhile the hydrogen atomís electron is left behind on the oxygen atom (O-), so it gains an extra negative charge.
This can all be put into the simple rule:
An acid is a proton donor
In truth this is a bit of an over-simplification because some molecules behave like acids even though they do not contain any hydrogen atoms which can give away protons, such as boron trichloride. Following the work of G.N.Lewis, most chemists now define acids as molecules which can accept an electron-pair.
Nevertheless the simple rule stated above applies in most cases met in organic chemistry.
Why are acids important in the History of the Universe?
Acids were essential in history for several reasons:
The which are the building blocks of contain acid.
The , which is vital in the geological cycle, depends in part upon the fact that rain is a weak acid, carbonic acid.
And the electrical forces between electrons left behind after protons are lost by phosphate drives which is lifeís major store.
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