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30 POINTS!!!
Acid: Pka:
H20 15.7
NH3 38
HCL -8
NH4+ 9.2

Given the list of pKa values, which acid will have the largest amount of conjugate base present in the solution at equilibrium?

H2O


NH3


NH4+


HCl

Respuesta :

Dejanras
Answer is: HCl (hydrochloric acid) will have the largest amount of conjugate base.

Hydrochloric acid is the strongest acid present in this question, because it has largest Ka value:
pKa(HCl) = -8.
Ka(HCl) = 10∧(-pKa).
Ka(HCl) = 10⁸.
Chemical dissotiation of hydrochloric acid:
HCl(aq) → H⁺(aq) + Cl⁻(aq).
Ka(HCl) = [H⁺]·[Cl⁻] / [HCl].
Concentration of Cl⁻ ions (conjugate base of hydrochloric acid) is very high.
tаskmasters
The answer to this question is HCL. Since pKa = -log[Ka], we have
                                Ka = 10^(-pKa)
so with HCL, pKA = -8 and so
                                Ka = 10^(-(-8)) = 10^8
which is a very large Ka value implying full completion of reaction.
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