Specify which indicator or indicators you would use for the following titrations:

a. HCOOH versus NaOH

b. HCl versus KOH

c. HNO3 versus CH3NH2

1. Phenolphthalein

2. Phenolphthalein

3. Methyl orange

Explanation:

Different indicators are used by knowing the relative strength of the acid and the bases I. e whether the acid is strong or weak, so also the base.

The following answers are obtainable:

1. Phenolphthalein

We use this indicator for a weak base and a strong acid. Formic acid is a weak organic acid while sodium hydroxide is a strong base

2. Phenolphthalein

We use this indicator because we are dealing with a strong acid and a strong base. Hydrochloric acid is a strong acid while potassium hydroxide is a strong base

3. Methyl orange

This is because we are dealing with a strong acid and a weak base