Acid strength

One of the multiple choice questions brings up the idea of strong vs. weak acids and bases:

Which of the following is the strongest acid?
a.KOH (aq)
b.HClO₄ (aq)
c.HC₂H₃O₂ (aq)
d.H₂0 (aq)
e.NH₃ (aq)

Strong acids (and bases) are those which ionize/dissolve completely when added to water. Let's approach this question by first identifying each substance listed. KOH is a strong base, so it's definitely not the strongest acid. H₂O is water, doesn't seem like a strong acid. NH₃ is ammonia, it's a weak base. That leaves us with HClO₄ and HC₂H₃O₂. Perchloric acid is a strong acid, HC₂H₃O₂ is vinegar, a weak acid. By eliminating the bases and water, you turn this from a 20% chance of random guessing, to a 50:50 chance.

Check Table 4.2 in the text, the acids and bases listed in black are all "strong", those listed in pink are weak. For our purposes, any acid or base that is not listed in that table as being "strong" should be considered weak.

Other questions, let me know...