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Dihydrogen phosphate is an inorganic ion with the formula [H 2 PO 4] −.Phosphates occur widely in natural systems. [1]These sodium phosphates are artificially used in food processing and packaging as emulsifying agents, neutralizing agents, surface-activating agents, and leavening agents providing humans with benefits.
The last one is pyrophosphate [P 2 O 7] 4−. The pyrophosphates are mostly water-soluble. Likewise, tripolyphosphoric acid H 5 P 3 O 10 yields at least five anions [H 5−k P 3 O 10] k−, where k ranges from 1 to 5, including tripolyphosphate [P 3 O 10] 5−. Tetrapolyphosphoric acid H 6 P 4 O 13 yields at least six anions, including ...
The thermal process produces phosphoric acid with a very high concentration of P 2 O 5 (about 85%) and a low level of impurities. However, this process is more expensive and energy-intensive than the wet process, which produces phosphoric acid with a lower concentration of P 2 O 5 (about 26-52%) and a higher level of impurities.
Some phosphorus oxoacids have two or more P atoms in different oxidation states. One example is Isohypophosphoric acid, H 4 P 2 O 6 (or H(OH)(O)P−O−P(O)(OH) 2), a tetraprotic acid and isomer of hypophosphoric acid, containing P in oxidation state +3 and +5; Phosphoric anhydride P 4 O 10 Some phosphoric acids
Hypophosphoric acid is a mineral acid with the formula H 4 P 2 O 6, with phosphorus in a formal oxidation state of +4. In the solid state it is present as the dihydrate, H 4 P 2 O 6 ·2H 2 O. In hypophosphoric acid the phosphorus atoms are identical and joined directly with a P−P bond.
At pH 1 or lower, the phosphoric acid is practically undissociated. Around pH 4.7 (mid-way between the first two pK a values) the dihydrogen phosphate ion, [H 2 PO 4] −, is practically the only species present. Around pH 9.8 (mid-way between the second and third pK a values) the monohydrogen phosphate ion, [HPO 4] 2−, is the only species ...
P 4 + 4 OH − + 4 H 2 O → 4 H 2 PO − 2 + 2 H 2. Any phosphites produced in this step can be selectively precipitated out by treatment with calcium salts. The purified material is then treated with a strong, non-oxidizing acid (often sulfuric acid) to give the free hypophosphorous acid: H 2 PO − 2 + H + → H 3 PO 2. HPA is usually ...
Element Negative states Positive states Group Notes −5 −4 −3 −2 −1 0 +1 +2 +3 +4 +5 +6 +7 +8 +9 Z; 1 hydrogen: H −1 +1: 1 2 helium: He 0 18