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For example, according to weak sustainability, replacing a natural forest with a park or agricultural land can be considered sustainable if the recreational or economic value equal the value of the biodiversity lost and further environmental impact caused. According to strong sustainability, cutting down trees in a natural forest and planting ...
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.
When some strong acid is added to an equilibrium mixture of the weak acid and its conjugate base, hydrogen ions (H +) are added, and the equilibrium is shifted to the left, in accordance with Le Chatelier's principle. Because of this, the hydrogen ion concentration increases by less than the amount expected for the quantity of strong acid added.
A weak acid may be defined as an acid with pK a greater than about −2. An acid with pK a = −2 would be 99 % dissociated at pH 0, that is, in a 1 M HCl solution. Any acid with a pK a less than about −2 is said to be a strong acid. Strong acids are said to be fully dissociated.
The strength of a strong acid is limited ("leveled") by the basicity of the solvent. Similarly the strength of a strong base is leveled by the acidity of the solvent. When a strong acid is dissolved in water, it reacts with it to form hydronium ion (H 3 O +). [2] An example of this would be the following reaction, where "HA" is the strong acid:
For a strong acid-strong base titration monitored by pH, we have at any i'th point in the titration = [+] [] where K w is the water autoprotolysis constant.. If titrating an acid of initial volume and concentration [+] with base of concentration [], then at any i'th point in the titration with titrant volume ,
However, the acids and bases must differ greatly in strength, e.g. one strong acid and one very weak acid. [1] Therefore, the two acids must have a pK a (or pK b) difference that is as large as possible. For example, the following can be separated: Very weak acids like phenols (pK a around 10) from stronger acids like carboxylic acids [1] (pK a ...
Acetic acid is an example of a weak acid. The pH of the neutralized solution resulting from HA + OH − → H 2 O + A −. is not close to 7, as with a strong acid, but depends on the acid dissociation constant, K a, of the acid. The pH at the end-point or equivalence point in a titration may be calculated as follows.