Suppose that 15.0 mL of 0.15 m NH₃(aq) is titrated with 0.10 m HCl(aq).

(a) What is the initial pH of the 0.15 m NH₃(aq)?

(b) What is the pH after the addition of 15.0 mL of 0.10 m HCl(aq)?

(c) What volume of 0.10 m HCl(aq) is required to reach halfway to the stoichiometric point?

(d) Calculate the pH at the halfway point.

(e) What volume of 0.10 m HCl(aq) is required to reach the stoichiometric point?

(f) Calculate the pH at the stoichiometric point.

(g) Use Table 6H.2 to select an indicator for the titration.

Transcribed Image Text:

TABLE 6H.2 Indicator Color Changes* pH range of color change Indicator thymol blue methyl orange bromophenol blue bromocresol green methyl red litmus bromothymol blue phenol red thymol blue phenolphthalein alizarin yellow R alizarin pKin 1.7 3.4 3.9 4.7 5.0 6.5 7.1 7.9 8.9 9.4 11.2 11.7 1.2 to 2.8 3.2 to 4.4 3.0 to 4.6 3.8 to 5.4 4.8 to 6.0 5.0 to 8.0 6.0 to 7.6 6.6 to 8.0 8.0 to 9.6 8.2 to 10.0 10.1 to 12.0 11.0 to 12.4 Color of acid form red red yellow yellow red red yellow yellow yellow colorless yellow red Color of base form yellow yellow blue blue yellow blue blue red blue pink red purple