The
prefix “Hypo” use for those oxy acid having lower oxidation state than either
“us” or “ic” oxy acid for example Hypophosphorous acid (H3PO2),
Hypophosphoric acid (H4P2O6) and hyposulphurous acid (H2S2O4).
For exitence of hypo acid for an oxy
acid, it must be a parent oxy acid contains at least two hydrogen atoms except nitrous acid (HNO2).
Example;
Which of the following parent acid does/do not has correspong “Hypo” oxy acid?
(A)
HNO3 (B) H3PO4 (C) H2SO4
(4) HClO4
Answer
Key : A and D
The
prefix “per” used to an oxy acid which
is obtained by adding one oxygen atom to the a respective “ic oxy acids” for
example sulphuric acid (H2SO4) and its per sulphuric
acid/caro’s acid is (H2SO5)
which is contains one (-O-O-) peroxy linkage. And also hydrochloric acid (HClO4)
and Perhydrochloric acid (HClO5).
Per-acid
having two central atoms is formed by adding one oxygen atom to its
pyro-ic-acid. For pyrosulphuric acid (H2S2O7)
and pyrophosphoric acid (H4P2O7) and their
per-oxy-acids are perdisulphuric acid/marshal’s
acid (H2S2O8) and perdiphosphoric acid
(H4P2O8) repectivily.
Conclusion: If –OH group
attach to that central atom having lone pair and vacant orbitals and tendency
to expand its orbitals then there is possibility of tautomerised. If size of
central atom is should be small then there will be no tautomerism, so in case
of Antomony,Arsenic while drawing structure of oxy acids all the hydrogen atoms
are converted into –OH groups and they are symmetrical bonded to all central
atoms. How ever this rule is not applicable for those oxy acidsof phosphorous
in which oxidation state of phosphorous is +1 or +3.
Basicity of an oxy acid is equal to number of
–OH groups presents in it exceptin oxy acid of boron. Oxy acid of boron does
not furnish H+ rather it act as Lewis acid.
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