Explain the titration of a strong acid and weak base.

Titration of Strong Acid and a Weak Base:
For explaining this type of titration let us consider an example of HCl which is strong acid and ammonium hydroxide i.e. NH₄OH which is a weak base. The reaction can be shown as:
NH₄OH (aq) + HCl (aq) ———> NH₄Cl (aq) + H₂O (l)

In this case the curve is similar to that in weak acid and strong base as shown in figure below. However, the equivalence point is below 7 due to the reaction of NH₄Cl formed at the neutralization with water. This reaction gives H⁺ ions. Also the equivalence point lies at pH=5.3 which makes it important to use an indicator which has an acidic ph for example:- Methyl orange. Though phenolphthalein suits the ph criteria but still is avoided as its color changes away from the equivalence point.