Summary of Section 3
- Phosphate is used in fertilisers and excess phosphate in natural water can cause eutrophication.
- Phosphorus has several acids including phosphoric and phosphorus acid. Note the higher oxidation number, or oxidation state, is indicated by the suffix -
ic
and the lower oxidation state by the suffix -
ous
.
- Generally for oxoacids if more than two oxidation numbers are involved, the prefixes
per
- and
hypo
- are used as well where
per
- denotes the highest oxidation number and
hypo
- the lowest oxidation number.
- Some acids of phosphorus are polyprotic. For instance, phosphoric acid:H3PO4(aq) = H+(aq) + H2PO4
−(aq)
H2PO4
−(aq) = H+(aq) + HPO4
2−(aq)
HPO4
2−(aq) = H+(aq) + PO4
3−(aq)
- Deprotonation of an acid yields its conjugate base or anion. In Equation 21 H2PO4
− is the conjugate base of phosphoric acid.
- Oxoacids and oxoanions can polymerise by condensation.
- Phosphorus also forms polyacids containing two or more acidic phosphorus centres.
- Polyphosphate can form chain or ring polymers.
- Adenosine triphosphate (ATP) stores energy in the body which is released upon its hydrolysis to adenosine diphosphate (ADP).
- The negative charges on ATP, ADP and DNA are counterbalanced by cations, usually magnesium.
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