Why do strong acids have weak conjugate bases? - Chemistry Stack Exchange
Describe the relationship between an acid and its conjugate base and a base The conjugate base of a strong acid is an extremely weak base, which is too. We can use this relationship to convert between the Ka for an acid HA and the Kb for its conjugate Thus the stronger the acid, the weaker its conjugate base. Jun 28, The reactions with most tendency to occur are between the strong acids in the top left-hand comer of the table and the strong bases in the.
11.12: Conjugate Acid-Base Pairs
On the other hand, ammonia is the conjugate base for the acid ammonium after ammonium has donated a hydrogen ion towards the production of the water molecule. Based on this information, it is clear that the terms "Acid", "Base", "conjugate acid", and "conjugate base" are not fixed for a certain chemical species; but are interchangeable according to the reaction taking place.
Strength of conjugates[ edit ] The strength of a conjugate acid is directly proportional to its dissociation constant. If a conjugate acid is strong, its dissociation will have a higher equilibrium constant and the products of the reaction will be favored. The strength of a conjugate base can be seen as the tendency of the species to "pull" hydrogen protons towards itself.
If a conjugate base is classified as strong, it will "hold on" to the hydrogen proton when in solution and its acid will not dissociate. On the other hand, if a species is classified as a strong acid, its conjugate base will be weak in nature. An example of this case would be the dissociation of Hydrochloric acid HCl in water.
Conjugate Acid-Base Pairs - Chemistry LibreTexts
Similarly, if an acid is weak, its conjugate base will be strong. Therefore, weak acids will have weak conjugate bases, unlike the misconception that they have strong conjugate bases. Identifying conjugate acid-base pairs[ edit ] The acid and conjugate base as well as the base and conjugate acid are known as conjugate pairs. The Advantages of the Brnsted Definition The Brnsted definition of acids and bases offers many advantages over the Arrhenius and operational definitions.
It expands the list of potential acids to include positive and negative ions, as well as neutral molecules.
It expands the list of bases to include any molecule or ion with at least one pair of nonbonding valence electrons. It explains the role of water in acid-base reactions: It can be expanded to include solvents other than water and reactions that occur in the gas or solid phases.
Conjugate acid - Wikipedia
It links acids and bases into conjugate acid-base pairs. It can explain the relationship between the strengths of an acid and its conjugate base.
It can explain differences in the relative strengths of a pair of acids or a pair of bases. It can explain the leveling effect of water the fact that strong acids and bases all have the same strength when dissolved in water. Because of these advantages, whenever chemists use the words acid or base without any further description, they are referring to a Brnsted acid or a Brnsted base. Pure water is both a weak acid and a weak base.