42

QUALITATIVE ORGANIC ANALYSIS

TABLE XVI

SOLUBILITY GROUP V, ALDKHYDKS, KIOTONKS, KSTKHS (ANHYDKIDKK),
ALCOHOLS, ETHERS, ETC. APPLY TIIK PIIKNYLHYDRAXINE TKST

Positive reaction.
Aldehyde or kc-
tone. Apply tests
to differentiate

(Anhydrides will inter-
fere. Sec page -15.)

ve test.

Esters (anhydrides), ,'ilcohols, ethers, unsatunitcd IIC.
Apply saponifies! ion lesi

Positive: reaction. Ks- ;Ne#;ilivc reaction. Alcohols,
tors and anhydrides ! el hers, unsatnrated IIC. Ap-

1 nlv a.cvl halide lest

j i .

1 Positive ivae- Negative reac-
fion. Alcohols' lion. Ethers
and unsat.u-
rnfed HC

/
Both aldehydes and ketones possckss tin* r-arhonyl ^roup (.!- -

arid their most important reactions are fhereiorc the typical
reactions of this group. Tho speed of reaction of the rarbonyl
group, and, to some extent also the kind of reaction, is dependent

. -

upon the groups united to the earbonyl. In aldehydes, R ••( < If,

the earbonyl group is united to a hydrogen atom, whereas in

./°.

ketones R-C— R', the aldfihyde hydro^c^n is replaced by a radical
of higher molecular weight. In additive reactions, the aldehydes
will therefore show a greater reaction velocity; individual ketoncs
will exhibit decreased reaction velocity with increase in molecular
weight of the radical R1. Differentiation between aldehydes and
ketones may be based upon this difference in the* ease of reaction.

Since the hydrogen of the -(/ - H is readily oxidized to hydroxyl,
another differentiation between aldehydes and kef ones is found
in differences in the ease of oxidation.
The earbonyl group increases the mobility of the hydrogens on adjacent
carbon atoms. For this reason, substitution by halogens taken place; more
readily with these classes of compounds than with the hydrocarbons.