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Anhydrides; Acid anhydride
Acid
off of a part of the water, the remaining part is
called the acid anhydride. General inorganic acid is
a member of the acid, the direct loss of a member of
the water to form the acid anhydride, the acid
anhydride, decided to change the valence of the
element. The organic acids is formed by two or more
molecules of the acid through the dehydration
reaction between molecules. Only the
oxygen-containing have acid anhydride and Anaerobic
acid haven't acid anhydride, it is anhydride.
Generally regarded as the oxides formed by the
acid-shrunk, and many of them are formed to the
original Acid by further reacting with water.
According to the nature of the acid, it can be
divided into : 1)Inorganic acid anhydride .By one or
two acid molecules formed shrink; Such as carbon
(acid) anhydride or carbon dioxide, CO2, NOx (acid)
anhydride or nitrous oxide N2O5; 2)Organic acids
anhydride, Consists of two unary acid molecule, or a
binary compound made of acid molecule has shrunk.
For example, B (acid) anhydride (CH3CO) 2O, phthalic
anhydride C6H4 (CO) 2O .
Common acid
anhydride:
|
H2SO4→ SO3 |
HPO3→ P2O5 |
CH3COOH→C4H6O3 |
|
H2SO4→ SO3 |
HNO3→ N2O5 |
N2O |
|
H2SO3→ SO2 |
HNO2→ N2O3 |
N2O4（Colorless gas） |
How to determine the
oxygen-containing acid anhydride?
Acid in the
non-metallic oxides is the same valence of
oxygen-containing acid anhydride. For example,
carbonate carbon is +4 valence then its anhydride is
carbon dioxide.
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