Use the following acid ionization constants to identify the correct decreasing order of base strengths. HF
K_a = 7.2 *10^-⁴
HNO₂
K_a = 4.5 *10^-⁴
HCN
K_a = 6.2 *10^-¹⁰

Question

Use the following acid ionization constants to identify the correct decreasing order of base strengths. HF K_a = 7.2 *10^-⁴ HNO₂ K_a = 4.5 *10^-⁴ HCN K_a = 6.2 *10^-¹⁰

Quizplus · Accepted Answer

The correct order of base strengths is CN^- > NO₂^- > F^-. This is because the stronger the acid, the weaker its conjugate base. HF is the strongest acid, so F^- is the weakest base. HCN is the weakest acid, so CN^- is the strongest base. HNO₂ is in between, so NO₂^- is in between in strength.

Use the Following Acid Ionization Constants to Identify the Correct