An aqueous solution of ammonium hydroxide is taken in a conical flask and titrated against standard hydrochloric acid from a burette. Which of the following is the most suitable indicator for this titration and what is the colour change observed at the end point?

Step-by-step solution

Ammonium hydroxide ( NH₄OH ) is a weak base and hydrochloric acid ( HCl ) is a strong acid. The salt formed at the equivalence point is ammonium chloride ( NH₄Cl ), which undergoes cationic hydrolysis to give an acidic solution ( pH For a strong acid-weak base titration, methyl orange is the suitable indicator. Since the indicator is added to the weak base in the conical flask, its initial colour in the basic medium is yellow. At the end point, the addition of a slight excess of strong acid changes the medium to ac