Answer: (a) NH3 + H20 ⇔ NH4⁺ + OH⁻ Kb = [tex]\frac{ [NH4][OH]}{[NH3]}[/tex]
(b) CN⁻ + H20 ⇔ HCN⁺ + OH⁻ Kb = [tex]\frac{ [HCN][OH]}{[CN]}[/tex]
(c) C5H5N + H20 ⇔ C5H5NH⁺ + OH⁻ Kb = [tex]\frac{[C5H5NH][OH]}{ [C5H5N]}[/tex]
(d) C6H5NH2 + H20 ⇔ C6H5NH3⁺ + OH⁻ Kb = [tex]\frac{[C6H5NH3][OH]}{[C6H5NH2] }[/tex]
Explanation: There are ways to calculate the strength of acids and bases. The pH is more commom but there is pKa, pKb, Ka and Kb. Ka and Kb are the dissociation constant for acids and bases, respectively.
Using the balanced equation of dissociation, Kb is calculated by dividing the concentration of the products with the concentration of the reagent.