THE SIMPLE NITROGEN AND SULFUR, COMPOUNDS 73

Several of the types mentioned in the above table tin* easily
affected by treatment with strong acids. This is especially true of
the hydroxylamine, nitroso, arid hydrazo compounds.

+ dil. H( -1

Hydrazounisolc

HC1-H2N—<

Problem 35.—What products arc formed when nryl nitro compounds are
reduced with zinc in
(<t) neutral solution,
(b) alkaline solution,
(n acid solution?
How may a similar variety of products be prepared by electrolytic reduc-
tion?
Problem 36.—\Vhut is formed when sodium rnothylatc acts as a. reducing
agent on nitrobenzene? Will reduction take plan* when hydrogen gas from
a Kipp generator is passed into boiling nitrobenzene?
In this series of indifferent nitrogen compounds, it, is not
essential, however, that an unknown bo limited t-o one* individual
class before proceeding with the work; the identification of the
products obtained by reduction or hydrolysis together with the
physical constants arid other properties of the original unknown,
will serve to simplify the procedure greatly.
Problem 37.—In a manner analogous with the explunai ion of the ben/idinc*
rearrangement, explain the formation of />-ammopheuol from phenyl hydroxyl-
amine and sulfurie acid. What is the, Hernidine rearrangement?
Problem 38.-—Hydra/0 compounds are colorless. Why do (lie samples
met with usually possess a yellow color. How can we explain I hat nitroHo-
benzene is gre.en only when in the liquid or vapor phase? What. HUfWHtion
can be given for the deepening of color when the nitropbenols arc converted
into their salts?
Discussion of Subgroup B.—With thci exception of formamide,
the common amides arc solids with fairly high melting-points and
usually limited solubility in ether and benzene. The nit/riles of the