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Nitrate, or NO3-, is the conjugate base of HNO3. The reaction resulting in the conjugate base of HNO3 is HNO3 + H2O → H3O+ + NO3-. In most cases, the acid molecule that remains after losing a hydrogen ion is an acid’s conjugate base. In this example, that
conjugate base is the nitrate. To conjugate an acid, it is necessary to place it in water to create a chemical reaction with the H2O molecules. HNO3 is an acid, and it releases a proton into the water as a result of the chemical reaction. This results in the creation of the nitrate conjugate base and a hydronium (H3O+) acid base. MORE FROM REFERENCE.COM For the reaction (really, equilibrium): NH3 + HNO3 = NH4+ + NO3- Ammonia (NH3) is the base, its conjugate acid is NH4+ and nitric acid (HNO3) is the acid with nitrate (NO3-) the conjugate base. For reactions like this you will get acid-conjugate base pair and a base-conjugate acid pair. If you can figure out which is the acid or base on the left side (or right side) of the equation, everything else pretty much falls into place). More For the reaction (really, equilibrium): NH3 + HNO3 = NH4+ + NO3- Ammonia (NH3) is the base, its conjugate acid is NH4+ and nitric acid (HNO3) is the acid with nitrate (NO3-) the conjugate base. For reactions like this you will get acid-conjugate base pair and a base-conjugate acid pair. If you can figure out which is the acid or base on the left side (or right side) of the equation, everything else pretty much falls into place). A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid donates a proton (H+) to a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a hydrogen ion. On the other hand, a conjugate base is what is left over after an acid has donated a proton during a chemical reaction. Hence, a conjugate base is a species formed by the removal of a proton from an acid, as in the reverse reaction it is able to gain a hydrogen ion.[1] Because some acids are capable of releasing multiple protons, the conjugate base of an acid may itself be acidic. In summary, this can be represented as the following chemical reaction: Johannes Nicolaus Brønsted and Martin Lowry introduced the Brønsted–Lowry theory, which proposed that any compound that can transfer a proton to any other compound is an acid, and the compound that accepts the proton is a base. A proton is a nuclear particle with a unit positive electrical charge; it is represented by the symbol H+ because it constitutes the nucleus of a hydrogen atom,[2] that is, a hydrogen cation. A cation can be a conjugate acid, and an anion can be a conjugate base, depending on which substance is involved and which acid–base theory is the viewpoint. The simplest anion which can be a conjugate base is the solvated electron whose conjugate acid is the atomic hydrogen. Acid–base reactions[edit]In an acid–base reaction, an acid plus a base reacts to form a conjugate base plus a conjugate acid. The acid loses a proton and the base gains a proton. In chemical diagrams which illustrate this, the new bond formed between the base and the proton is shown by an arrow that conventionally starts on an electron pair from the base and whose arrow-head ends at the hydrogen ion (proton) that will be transferred: In this case, the water molecule is the conjugate acid of the hydroxide ion after the latter received the hydrogen ion donated by
ammonium. On the other hand, ammonia is the conjugate base for the acid ammonium after ammonium has donated a hydrogen ion and produced the water molecule. Also, OH− can be considered as the conjugate base of H 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. If a species is classified as a strong acid, its conjugate base will be
weak.[3] An example of this case would be the dissociation of hydrochloric acid HCl in water. Since HCl is a strong acid (it dissociates to a great extent), its conjugate base
(Cl− On the other hand, if a species is classified as a weak acid its conjugate base will not necessarily be a strong base. Consider that acetate, the conjugate base of acetic acid, has a base dissociation constant (Kb) of approximately 5.6×10−10, making it a weak base. In order for a species to have a strong conjugate base it has to be a very weak acid, like water for example. Identifying conjugate acid–base pairs[edit]To identify the conjugate acid, look for the pair of compounds that are related. The acid–base reaction can be viewed in a before and after sense. The before is the reactant side of the equation, the after is the product side of the equation. The conjugate acid in the after side of an equation gains a hydrogen ion, so in the before side of the equation the compound that has one less hydrogen ion of the conjugate acid is the base. The conjugate base in the after side of the equation lost a hydrogen ion, so in the before side of the equation, the compound that has one more hydrogen ion of the conjugate base is the acid. Consider the following acid–base reaction: HNO3 + H 2O → H 3O+ + NO− 3 Nitric acid (HNO
Applications[edit]One use of conjugate acids and bases lies in buffering systems, which include a buffer solution. In a buffer, a
weak acid and its conjugate base (in the form of a salt), or a weak base and its conjugate acid, are used in order to limit the pH change during a titration process. Buffers have both organic and non-organic chemical applications. For example, besides buffers being used in lab processes, human blood acts as a buffer to maintain pH. The most important buffer in our bloodstream is the carbonic acid-bicarbonate buffer, which prevents drastic pH changes when CO Furthermore, here is a table of common buffers.
A second common application with an organic compound would be the production of a buffer with acetic acid. If acetic acid, a weak acid with the formula CH Ringer's lactate solution is an example where
the conjugate base of an organic acid, lactic acid, CH Table of acids and their conjugate bases[edit]Tabulated below are several examples of acids and their conjugate bases; notice how they differ by just one proton (H+ ion). Acid strength decreases and conjugate base strength increases down the table.
Table of bases and their conjugate acids[edit]In contrast, here is a table of bases and their conjugate acids. Similarly, base strength decreases and conjugate acid strength increases down the table.
See also[edit]
References[edit]
External links[edit]
Is NO3 the conjugate base of HNO3?The nitrate ion is the conjugate base of nitric acid, HNO3.
What is the base of acid HNO3?Nitric acid is a nitrogen oxoacid of formula HNO3 in which the nitrogen atom is bonded to a hydroxy group and by equivalent bonds to the remaining two oxygen atoms. It has a role as a protic solvent and a reagent. It is a conjugate acid of a nitrate.
Does HNO3 have a strong conjugate base?The conjugate base of HNO3 is NO3 -1, which is the nitrate polyatomic ion. The removal of the hydrogen ion, which is the same as a proton, makes the neutral conjugate acid a negatively charged conjugate base.
What is the conjugate base of NH3?∴NH2− is the conjugate base of NH3.
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