Question

A buffer is a solution of weak acid and its conjugate base or a weak base and its conjugate acid. It resists the change in $pH$ , when small amount of strong acid or base is added to it. Buffer solutions have wide applications.

$20.0mL$ of $0.10M$ of 1-aminopropane is titrated with $0.10M$ of $HCl$ . The $pH$ at the equivalence point is $p\simeq 6$ and the appropriate acid-base indicator. is Methyl red. (4.2-6.2) wright the right answer

Table 1.
Table 1: List of acid/base indicators

Common name	Transition range, $pH$	Color change
Methyl orange	3.2 - 4.4	red-orange
Methyl red	4.2 - 6.2	red-yellow
Phenol red	6.8 - 8.2	yellow-red
Phenolphthalein	8.0 - 9.8	colorless-red
Thymolphthalein	9.3 - 10.5	colorless-blue

Answer 1

For the titration between strong acid and weak base equivalence point occurs at ph 6 which is acidic in nature and methyl red is red in pH under 4.4 and yellow in pH over 6.2.