Chapter 16, Problem 136RQ

When 25 mL of 0.12 M aqueous ammonia is titrated with 0.12 M hydrobromic acid, what is the pH at the equivalence point? Select a good indicator for this titration from Table 16.7.

TABLE 16.7 Common Acid-Base Indicators

Indicator	Approximate pH Range over which the Color Changes	Color Change (lower to higher pH)
Methyl green	0.2-1.8	Yellow to blue
Thymol blue	1.2-2.8	Yellow to blue
Methyl orange	3.2-4.4	Red to yellow
Ethyl red	4.0-5.8	Colorless to red
Methyl purple	4.8-5.4	Purple to green
Bromocresol purple	5.2-6.8	Yellow to purple
Bromothymol blue	6.0-7.6	Yellow to blue
Phenol red	6.4-8.2	Yellow to red/violet
Litmus	4.7-8.3	Red to blue
Cresol red	7.0-8.8	Yellow to red
Thymol blue	8.0-9.6	Yellow to blue
Phenolphthalein	8.2-10.0	Colorless to pink
Thymolphthalein	9.4-10.6	Colorless to blue
Alizarin yellow R	10.1-12.0	Yellow to red
Clayton yellow	12.2-13.2	Yellow to amber