Which of the following bases has the weakest conjugate acid? A) CH₃COO⁻ B) C₆H₅O⁻ C) HSO₄⁻ D) H₂PO₄⁻

Question

Quizplus · Accepted Answer

The strength of a conjugate acid is inversely related to the strength of its base. Among the given options, $CH_3COO^-$ (A) is a relatively weak base, making its conjugate acid (acetic acid) moderately strong. $C_6H_5O^-$ (B), the phenoxide ion, is a stronger base due to resonance stabilization, which makes its conjugate acid (phenol) weaker compared to others. $HSO_4^-$ (C) is a relatively strong base, making its conjugate acid (sulfuric acid) very strong. $H_2PO_4^-$ (D) is also a relatively strong base, making its conjugate acid (dihydrogen phosphate) strong. Therefore, the phenoxide ion has the weakest conjugate acid because it is the strongest base among the options, and strong bases have weak conjugate acids.

Which of the Following Bases Has the Weakest Conjugate Acid