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The higher the proton affinity, the stronger the base and the weaker the conjugate acid in the gas phase.The (reportedly) strongest known base is the ortho-diethynylbenzene dianion (E pa = 1843 kJ/mol), [3] followed by the methanide anion (E pa = 1743 kJ/mol) and the hydride ion (E pa = 1675 kJ/mol), [4] making methane the weakest proton acid [5] in the gas phase, followed by dihydrogen.
A buffer solution is a solution where the pH does not change significantly on dilution or if an acid or base is added at constant temperature. [1] Its pH changes very little when a small amount of strong acid or base is added to it. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical ...
Bjerrum plot of speciation for a hypothetical monoprotic acid: AH concentration as a function of the difference between pK and pH. Carbonic acid is the formal Brønsted–Lowry conjugate acid of the bicarbonate anion, stable in alkaline solution. The protonation constants have been measured to great precision, but depend on overall ionic ...
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Speciation of ions refers to the changing concentration of varying forms of an ion as the pH of the solution changes. [1]The ratio of acid, AH and conjugate base, A −, concentrations varies as the difference between the pH and the pK a varies, in accordance with the Henderson-Hasselbalch equation.
When the difference between successive pK values is about four or more, as in this example, each species may be considered as an acid in its own right; [27] In fact salts of H 2 PO − 4 may be crystallised from solution by adjustment of pH to about 5.5 and salts of HPO 2− 4 may be crystallised from solution by adjustment of pH to about 10.
Guanidinium chloride is a weak acid with a pK a of 13.6. The reason that it is such a weak acid is the complete delocalization of the positive charge through three nitrogen atoms (plus a little bit of positive charge on carbon). However, some stronger bases can deprotonate it, such as sodium hydroxide: C(NH 2) + 3 + OH − ⇌ HNC(NH 2) 2 + H 2 O
A "weak" polyelectrolyte, by contrast, has a dissociation constant (pKa or pKb) in the range of ~2 to ~10, meaning that it will be partially dissociated at intermediate pH. Thus, weak polyelectrolytes are not fully charged in the solution, and moreover, their fractional charge can be modified by changing the solution pH, counter-ion ...