Question

how to compare acidic and basic strength

Answer 1

strength of an acid:depends on the conc. of hydronium ions present in an aqueous sol.of an acid.
strength of bases:depends on the conc. of the hydroxyl ions present in an aqueous solution of the alkali.

Answer 2

On comparing the strength of Acids and bases we have the following points:-

1. Strength of Acids are compared on the basis of their H+ ion releasing tendency when the acid is dissolved in water.

2. Strength of bases are compared on the basis of their OH¯ releasing tendency when the base is dissolved in water.

3. Strong bases and strong acids gets ionised easily. And the strength of these strong acids and bases is same. So the relative strength is not required to be compared.

4. Weak bases and weak acids don't get completely ionised, so their relative strengths are needed to be compared.