Part 1: What is the pH of a 0.18 M solution of methylammonium nitrate (CH3NH3NO3)? Kb for methylamine (CH3NH2) is 5.0 × 10-4.
Part 2: A 10 mL sample of 0.3 M NH4Cl is titrated with 0.1 M NaOH. What is the pH of the so- lution after 70 mL of NaOH has been added?
Part 3: Which of the following acid-base indicators should be used for the titration of NH3 with HBr? Kb of ammonia is 1.8 ×10-5.
1. Methyl red, color change red/yellow at 4.4 < pH < 6.2
2. Any of these is suitable.
3. Neutral red, color change red/yellow 6.8 < pH < 8.0
4. Phenolphthalein, color change colorless/red-violet 8.0 < pH < 10.0
5. None of these is suitable.