Missing question: HNO2(aq) 4.6×10−4 HCHO2(aq) 1.8×10−4 HClO(aq) 2.9×10−8 HCN(aq) 4.9×10−10 Answer is: the strongest conjugate base is CN⁻(aq), because it has highest base ionization constant. Chemical reaction: HCN(aq) ⇄ CN⁻(aq) + H⁺(aq). Ka(HCN) = 4,9·10⁻¹⁰. Ka · Kb = Kw; ionic product of water. Kb = Kw ÷ Ka. Kb(CN⁻) = 1·10⁻¹⁴ 4,9·10⁻¹⁰. Kb(CN⁻) = 2,04·10⁻⁵.
The question is incomplete. Complete question is: Consider the given acid ionization constants. identify the strongest conjugate base. HNO2(aq) 4.6×10−4 HCHO2(aq) 1.8×10−4 HClO(aq) 2.9×10−8 HCN(aq) 4.9×10−10 ......................................................................................................................... Correct Answer: option 4: HCN(aq) 4.9×10−10
Reason: According to Lowry and Bronsted theory of acid and base. Stronger the acid, weaker will be the conjugate base.
In present case, ionization constant is highest of HCN i.e. 4.9×[tex] 10^{-10} [/tex]. This signifies that, it is the strongest acid. Hence, conjugate base associated with this acid (i.e. [tex] CN^{-} [/tex]) is the weakest.
