Construct a rough plot of pH versus volume of base for the titration of 25.0 mL of 0.050 M HCN with 0.075 M NaOH.
(a) What is the pH before any NaOH is added?
(b) What is the pH at the halfway point of the titration?
(c) What is the pH when 95% of the required NaOH has been added?
(d) What volume of base, in milliliters, is required to reach the equivalence point?
(e) What is the pH at the equivalence point?
(f) What indicator would be most suitable for this titration? (Figure 17.11.)
(g) What is the pH when 105% of the required base has been added?

Data given in Figure 17.11

Transcribed Image Text:

2 3 Crystal violet Cresol red Thymol blue 5 6 Erythrosin B 2,4-Dinitrophenol Bromphenol blue Methyl orange Bromcresol green Methyl red 8 Eriochrome black T Bromcresol purple Alizarin 10 Bromthymol blue Phenol red 10 I m-Nitrophenol 11 o-Cresolphthalein Phenolphthalein 12 Thymolphthalein 13 14 Alizarin yellow GG Figure 17.11 Common acid-base indicators. The color changes occur over a range of pH values. Notice that a few indicators have color changes over two different pH ranges.