All strong acid and bases are equally ionized and water is amphoteric. So they have the same acidic or basic strength in water. This is known as the levelling effect.

The strength of acids also depends upon the solvent. Acetic acid is not receptive to take up protons and has to be forced. Thus acids HCIO4, H2S04, HCl and HN03 which have nearly the same strength in water follow the order of HClO4> H2SO4 > HCl > HNO3 in acetic acid.

The real strength of acids can be judged by solvents. On the basis of proton interaction, solvents can be classified into four types:

Protophilic solvents: Solvents that have a greater tendency to accept protons, i.e., water, alcohol, liquid ammonia, etc.
Protogenic solvents: Solvents that have the tendency to produce protons, i.e., water, liquid hydrogen chloride, glacial acetic acid, etc.
Amphiprotic solvents: Solvents that act both as protophilic or protogenic, e.g., water, ammonia, ethyl alcohol, etc.
Aprotic solvents: Solvents which neither donate nor accept protons, e.g., benzene, carbon tetrachloride, carbon disulphide, etc.

HCI acts as an acid in the water, stronger acid in NH3, weak acid in CH3COOH, neutral in C6H6 and a weak base in HF.

	Created by nadia sweet about 5 years ago

blood buffer and how the buffer solutions work