Chemistry textbooks routinely assign water a value of 15.74 for this quantity, even though decades of experiments have shown that estimate is too high. For 10 points each:
[10m] Name this molecular property which decreases as a compound becomes more acidic. This quantity and the pH determine the degree of ionization in the Henderson-Hasselbalch equation.
ANSWER: pKa [or the negative logarithm of the acid dissociation constant; or the negative logarithm of the Ka, but reject any partial answers that do not include all three parts; prompt on pKw; reject “Ka” or “acid dissociation constant” by themselves]
[10e] Water’s actual pKa is this two-digit integer, the typical upper bound of the pH scale.
ANSWER: 14
[10h] The confusion stems from incorrectly using water’s molarity in the law of mass action, rather than this dimensionless quantity, which is defined to be 1 for all pure solids and liquids.
ANSWER: activity [reject “activity coefficient”]
<Adam Silverman, Science - Chemistry> ~20758~ <Editor: Adam Silverman>