Hi, can anyone clarify this learning objective?
Show how the acidity constant of an acid is related to the basicity constant of its conjugate base
Thanks!
Acidity and Basicity Relationship
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Re: Acidity and Basicity Relationship
If I am correct, Ka x Kb = Kw = 10^-14, with Ka and Kb being the acidity and basicity constants, respectively. The acidity and basicity constants will multiply to the equilibrium constant of water (which as 25 degrees C is 10^-14).
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Re: Acidity and Basicity Relationship
Ka * Kb = Kw . In a problem if you are given the Kb value, but are dealing with that base's conjugate acid. You can convert that Kb value to the Ka value by doing (1 * 10^-14)/Kb to find Ka for that conjugate acid you are dealing with.
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Re: Acidity and Basicity Relationship
Hi Lexi,
Others before me have stated the mathematical description between the Kb and Ka of an acid/base conjugate pair. In terms of rationalizing it, rather than simply memorizing, a strong acid will always have a weak conjugate base and a weak acid will always have a strong conjugate base pair. If an acid more willingly deprotonates, then it would logically follow that the base is a more stable form and will not protonate to the same extent. Whether or not the acid or base is more preferred at equilibrium, one can look at the relative strengths of both species. The more stable species will dominate, such that at any equilibrium, the aid or base must be favored (unless both are equally favored).
Others before me have stated the mathematical description between the Kb and Ka of an acid/base conjugate pair. In terms of rationalizing it, rather than simply memorizing, a strong acid will always have a weak conjugate base and a weak acid will always have a strong conjugate base pair. If an acid more willingly deprotonates, then it would logically follow that the base is a more stable form and will not protonate to the same extent. Whether or not the acid or base is more preferred at equilibrium, one can look at the relative strengths of both species. The more stable species will dominate, such that at any equilibrium, the aid or base must be favored (unless both are equally favored).
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