Complete the following table, which lists information about the measured acid dissociation constants of three unknown weak acids. Note: be sure each number you put in the table has the correct number of significant digits. acid K a pKa relative strength 3.72 A B ☐ 9.3 C 8.112 × 5

Write the chemical equation for the ionization of caffeine, a weak base. The chemical formula of caffeine is C8H10N4O2.

Pure liquid ammonia ionizes in a manner similar to that of water. (a) Write the equilibrium for the autoionization of liquid ammonia. (b) Identify the conjugate acid form and the base form of the solvent. (c) Is NaNH2 an acid or a base in this solvent? (d) Is ammonium bromide an acid or a base in this solvent?

Predict whether each of these is a Lewis acid or a Lewis base. (Hint: Drawing a Lewis structure for a molecule or ion often helps to make such predictions.) (a) PH3 (b) BCl3 (c) H2S (d) NO2 (e) Ni2+ (f) CO

1. Which of the following can act as a Lewis acid? (Hint : In each case, draw the Lewis electron dot structure of the molecule or ion. Are there lone pairs of electrons on the central atom? If so, it can be a Lewis base. Does the central atom lack an electron pair? If so, it can behave as a Lewis acid.) PH3 BCl3 H2S HS−