Page 134 - Academic Press Encyclopedia of Physical Science and Technology 3rd InOrganic Chemistry

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Encyclopedia of Physical Science and Technology EN007C-307 June 29, 2001 19:40

Halogen Chemistry 211

FIGURE 1 Standard reduction potentials for Cl, Br, and I species in acid and alkaline aqueous solutions.

or by treating ClO 2 O with water. The hypochlorite anion, OBr < OI . The reaction of hypoiodite with methyl
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OCl , is also an effective bleach. Calcium hypochlorite is ketones forms the basis of the iodoform (CHI 3 ) test for
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used for swimming-pool sanitation and bleaching powder. CH 3 C O groups in organic compounds:
Liquid bleach is an alkaline solution of NaOCl with a
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RC( O)CH 3 + 3OI → RC( O)O + 2OH + CHI 3 .
chlorine content ranging from 5 to 12%.
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Hypochlorites react with ammonia and organic amines
to form chloramines. The “chlorine” odor of water treated HOCl is also used industrially to manufacture hydrazine,
with hypochlorite is actually due to the chloramines pro- chlorhydrins, and α-glycols.
duced by action of the acid on bacteria. Hypobromites
oxidize amines to N 2 .
C. Halous Acids and Halite Salts
Hypohalous acids are useful halogenating agents for
both aromatic and aliphatic compounds, the ease of Chlorous acid is the least stable of all the oxyacids of
aromatic halogenation increasing in the order OCl < chlorine. It can be prepared by treating a suspension of
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