CHAPTER III
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS

HYDROCARBONS AND THEIR OXYGEN AND HALOGEN
DERIVATIVES

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THE study of the elements of organic chemistry will have made
familiar the characteristic reactions of the common classes of
organic compounds, viz., the reactions of the car boxy 1 group, the
carbonyl group, the hydroxyl group, the nitro group, the amine
group, the aryl hydrocarbon group, etc. The following discus-
sion, together with the experimental work in Chapter IX, will
consist of a .partial review of the facts that are furnished so plenti-
fully in a general course in organic chemistry. This review will
offer an opportunity for a reclassification of the information which
is unfortunately too often first studied in a memorizing fashion.
A systematic review from a different standpoint and a regrouping
of this information for the purposes of qualitative analysis is of
value as a general training for the chemist.

Qualitative organic analysis is possible because of the facts
of homology; all the members in a given homologous series
exhibit the same kind of chemical reactions, but they differ in the
velocity of reaction. Another important problem for considera-
tion is the effect of a given atom or group of atoms in modifying
the homologous tests of other groups simultaneously present in
the molecule. It is one of the functions of qualitative analysis
to teach some of this detailed information, particularly in connec-
tion with the actual laboratory study.

Most of the reactions to be discussed are adaptable to the
differentiation between various classes of possibilities within a
given solubility group; others possess value mainly in testing for
a limited number of individual compounds ; a third type is adapted
mainly to quantitative work after a search has been limited to a

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