Chapter 17 -- Sample problem

Ranking a group of acids and bases in order of increasing pH
Catagorize list into acidic, basic and neutral solutions.

Examine each list entry. Consider:

Is it a strong acid or a strong base? (these must be memorized)
Is it an organic acid? (look for the -COOH group)
Does it contain nitrogen (potentially a weak base, but not always!)
Is it a salt? If yes then consider the cation and anion:
- Is the cation the conjugate acid of a weak base?
- Is the anion the conjuage base of a weak acid?
- Is the salt neutral?

0.05 M NH₃: weak base, contains nitrogen
0.2 M HNO₃: strong acid
0.05 M CH₃COOH: weak acid (organic)
0.05 M Ca(OH)₂: strong base
0.05 M NH₄Cl: conjugate acid of weak base (NH₄⁺/NH₃, Cl^-, no effect)
0.05 M CH₃COONa: conjugate base of weak acid (CH₃COO^-/CH₃COOH, Na⁺ no effect
0.1 M H₂SO₄: strong acid for loss of first proton, weak acid for loss of second
0.1 M NaCl: netural
0.05 M NaOH: strong base
0.05 M CF₃COOH: weak acid (organic), fluorine atoms tend to withdraw electrons, weakening the OH bond.