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62 Chapter 5
6. In the titration of HCl with NH3, which of the following
indicators is most suitable?
(a) Phenolphthalein (b) EDTA (c) Methyl Red (d) Thymolphtha-
lein
LONG QUESTIONS ON CHAPTERS 4 AND 5
1. Determine the concentration of HCO; in 0.15 M carbonic acid,
H2CO3, given that Ka(1) = 4.2 x and Ka(2) = 5.6 x lo-".
2. Determine the pH of the following buffer solution containing
equal volumes of 0.35 M CH3C02H and 0.15 M CH3C02Na,
given that Ka(CH3C02H) = 1.8 x lo-' at 298 K.
3. What is the pH of a solution after the addition of 30 cm3 0.1 M
CH,NH,,,,) in a titration with 25 cm3 0.1 M HCl(aql, given that
Kb(CH3NH2(aq)) = 4.4 x at 298 K.
