Reactions
Phosphorous acid on heating at 200 °C converts to phosphoric acid and phosphine:
- 4 H3PO3 → 3 H3PO4 + PH3
In practice this reaction yields a number of undefined phosphorus suboxides as well.
Phosphorous acid is a moderately strong dibasic acid. It reacts with alkalis forming acid phosphites and normal phosphites. Thus, reaction with sodium hydroxide gives sodium dihydrogen phosphite and disodium hydrogen phosphite, but not trisodium phosphite, Na3PO3 as the third (P-bound) hydrogen is not acidic.
- H3PO3 + NaOH → NaH2PO3 + H2O
- H3PO3 + 2 NaOH → Na2HPO3 + 2H2O
Phosphorous acid is a powerful reducing agent. When treated with a cold solution of mercuric chloride, a white precipitate of mercurous chloride forms:
- H3PO3 + 2 HgCl2 + H2O → Hg2Cl2 + H3PO4 + 2 HCl
Mercurous chloride is reduced further by phosphorous acid to mercury on heating or on standing:
- H3PO3 + Hg2Cl2 + H2O → 2 Hg + H3PO4 + 2 HCl
Read more about this topic: Phosphorous Acid
Famous quotes containing the word reactions:
“We have all had the experience of finding that our reactions and perhaps even our deeds have denied beliefs we thought were ours.”
—James Baldwin (1924–1987)
“Prolonged, indiscriminate reviewing of books is a quite exceptionally thankless, irritating and exhausting job. It not only involves praising trash but constantly inventing reactions towards books about which one has no spontaneous feeling whatever.”
—George Orwell (1903–1950)
“In this Journal, my pen is a delicate needle point, tracing out a graph of temperament so as to show its daily fluctuations: grave and gay, up and down, lamentation and revelry, self-love and self-disgust. You get here all my thoughts and opinions, always irresponsible and often contradictory or mutually exclusive, all my moods and vapours, all the varying reactions to environment of this jelly which is I.”
—W.N.P. Barbellion (1889–1919)