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Although ammonia is well known as a weak base, it can also act as an extremely weak acid. It is a protic substance and is capable of formation of amides (which contain the NH − 2 ion). For example, lithium dissolves in liquid ammonia to give a blue solution (solvated electron) of lithium amide: 2 Li + 2 NH 3 → 2 LiNH 2 + H 2
For example, carbon monoxide is a very weak Brønsted–Lowry base but it forms a strong adduct with BF 3. In another comparison of Lewis and Brønsted–Lowry acidity by Brown and Kanner, [ 19 ] 2,6-di- t -butylpyridine reacts to form the hydrochloride salt with HCl but does not react with BF 3 .
An example of a weak base is ammonia. It does not contain hydroxide ions, but it reacts with water to produce ammonium ions and hydroxide ions. [4] The position of equilibrium varies from base to base when a weak base reacts with water. The further to the left it is, the weaker the base. [5]
A strong base is a basic chemical compound that can remove a proton (H +) from (or deprotonate) a molecule of even a very weak acid (such as water) in an acid–base reaction. Common examples of strong bases include hydroxides of alkali metals and alkaline earth metals, like NaOH and Ca(OH) 2, respectively. Due to their low solubility, some ...
On the other hand, if a chemical is a weak acid its conjugate base will not necessarily be strong. Consider that ethanoate, the conjugate base of ethanoic acid, has a base splitting constant (Kb) of about 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, acetic acid is a weak acid which has a = 1.75 x 10 −5. Its conjugate base is the acetate ion with K b = 10 −14 /K a = 5.7 x 10 −10 (from the relationship K a × K b = 10 −14), which certainly does not correspond to a strong base. The conjugate of a weak acid is often a weak base and vice versa.
In aqueous solution, ammonia deprotonates a small fraction of the water to give ammonium and hydroxide according to the following equilibrium: . NH 3 + H 2 O ⇌ NH + 4 + OH −.. In a 1 M ammonia solution, about 0.42% of the ammonia is converted to ammonium, equivalent to pH = 11.63 because [NH +
The ECW model is quantitative model that describes and predicts the strength of Lewis acid base interactions, -ΔH . The model assigned E and C parameters to many Lewis acids and bases. Each acid is characterized by an E A and a C A. Each base is likewise characterized by its own E B and C B. The E and C parameters refer, respectively, to the ...