Acid

Explain clearly the difference between a strong acid and a weak acid.
Give one example of each.
What is meant by the ionic product for water, Kw ?
Define pH and hence calculate the pH of a solution of
a) 0.01 M hydrochloric acid
b) 0.1 M sodium hydroxide
c) 0.2 M sulphuric acid
d) 0.1 M butanoic acid, given that Ka = 1.51 x 10-5