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Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula H 3 P O 4.
Dissociation of pyrophosphoric acid H 4 P 2 O 7 generates four anions, [H 4−k P 2 O 7] k−, where the charge k ranges from 1 to 4. The last one is pyrophosphate [P 2 O 7] 4−. The pyrophosphates are mostly water-soluble.
When both the standard enthalpy change and acid dissociation constant have been determined, the standard entropy change is easily calculated from the equation above. In the following table, the entropy terms are calculated from the experimental values of pK a and ΔH ⊖. The data were critically selected and refer to 25 °C and zero ionic ...
Hypophosphoric acid can be prepared by the reaction of red phosphorus with sodium chlorite at room temperature. [2]2 P + 2 NaClO 2 + 2 H 2 O → Na 2 H 2 P 2 O 6 + 2 HCl. A mixture of hypophosphoric acid, phosphorous acid (H 3 PO 3) and phosphoric acid (H 3 PO 4) is produced when white phosphorus oxidises in air when partially immersed in water.
K a is variously named a dissociation constant, [3] an acid ionization constant, [2]: 668 an acidity constant [1] or an ionization constant. [ 2 ] : 708 It serves as an indicator of the acid strength: stronger acids have a higher K a value (and a lower p K a value).
Hypophosphorous acid was first prepared in 1816 by the French chemist Pierre Louis Dulong (1785–1838). [4]The acid is prepared industrially via a two step process: Firstly, elemental white phosphorus reacts with alkali and alkaline earth hydroxides to give an aqueous solution of hypophosphites:
For K′ 3 there are three different dissociation constants — there are only three possibilities for which pocket is filled last (I, II or III) — and one state (I–II–III). Even when the microscopic dissociation constant is the same for each individual binding event, the macroscopic outcome (K′ 1, K′ 2 and K′ 3) is not equal. This ...
An ICE table or RICE box or RICE chart is a tabular system of keeping track of changing concentrations in an equilibrium reaction. ICE stands for initial, change, equilibrium . It is used in chemistry to keep track of the changes in amount of substance of the reactants and also organize a set of conditions that one wants to solve with. [ 1 ]