Acids and Bases: Central Concepts in Organic Chemistry

Which of the following statements best describes the relationship between acid strength and the stability of its conjugate base?

Given the following reaction: $\mathrm{CH_3COOH} + \mathrm{NH_3} \rightleftharpoons \mathrm{CH_3COO^-} + \mathrm{NH_4^+}$, use the provided $pK_a$ values ($pK_a$ of acetic acid = 4.8, $pK_a$ of ammonium ion = 9.4) to calculate the equilibrium constant $K_{eq}$ for the reaction.

Which of the following compounds is the strongest acid? Use the $pK_a$ values: methyl alcohol ($pK_a = 15.5$), acetic acid ($pK_a = 4.76$), methylamine ($pK_a = 40$), and ammonia ($pK_a = 36$).