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Summary

Acids and Bases

Acids and Bases can be defined many ways the most common being Brønsted-Lowry acids and bases and Lewis acids and bases

In aqueous solution an acid will form the hydronium ion H₃O⁺ and a base will form OH^- ions.

Common acids include;

1. Hydrochloric acid
2. Sulphuric acid
3. Nitric Acid
4. Carboxylic acid, R1 can be any group or chain
5. Ammonium ion, again R1 can be any group or chain

Common bases include;

1. Sodium hydroxide
2. Ammonia
3. Sodium bicarbonate, commonly known as baking soda
4. Magnesium hydroxide
5. Hydrazine

pk_a, pk_b and pk_w

pk_a is defined as with the derivation of k_a here

pk_b is defined as with the derivation of k_b here

pk_a and pk_b are realated by pk_w which is the acidity constant of pure water. It is defined as follows

pk_w relates pk_a and pk_b as follows

pk_b values are not usually tabluated, instead as a result of this easy relationship pk_a values are usually the ones noted.

Reactions

In order for a acid and base reaction to work the pk_a forthe acid must be lower. The greater the difference in pk_a values the faster the reaction will proceed.

A table of pk_a values can be found here

Common reactions include the following examples

Indicators

Indicators are weak acids in which the acid and conjugate base has different colours. They provide a useful indicator for the end points of reactions, where the pH at the end is known. A table of selected indicators follows

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Acids

Bases

pK_a, pK_b and pK_w

Common Reactions