Synthetic Inorganic Chemistry

264 OXY-ACIDS AND SALTS OF THE NON-METALS

agent. This is quite in accord with what we have already found
in other cases, namely, that the stability of the acid is greater the
higher the valence of the principal element. It is also seen that
the nitrite ion alone is not the oxidizing agent; the presence of
hydrogen ions is necessary.

(6) Reducing Action of Nitrous Acid. To about 0.1 gram of

sodium nitrite and 100 cc. of cold water in a beaker add 10 cc.

of 6N H2SO4. To this solution add drop by drop with con-

stant stirring 0.1 formal KMnC>4, until the pink color pro-

duced by each drop disappears more and more slowly and

finally 1 drop more produces a permanent pink color.

The permanganate oxidizes the nitrous acid to nitric acid,

5HNO 2 + 2KMnO 4 + 3H2SO4 -»• K2SO4 + 2MnSO 4 +

3H 2 O + 5HNO 3

The reaction proceeds so sharply to completion, and the intense
color of the permanganate serves as such an excellent indicator,
that it is very easy to estimate the amount of nitrite from the
volume of a solution of KMnO 4 of known strength that it will
decolorize.

GENERAL QUESTIONS VIII

THE OXY-ACIDS AND SALTS OF THE NON-METALS

1. Make a table, in the first column of which place the formulas
   of hypochlorous acid, chlorous acid, chloric acid, perchloric acid,
   hypobromous acid, bromic acid, hypoiodous acid, iodic acid, two
   per-iodic acids differing in degree of hydration, sulphurous acid,
   sulphuric acid, nitrous acid, nitric acid. In the second column
   give the valence of the element in the particular acid; in the third
   column the formula of the anhydride; in the fourth column the
   word gas, liquid, solid, or hyp., according to the state of aggrega-
   tion of the anhydride at ordinary temperature, hyp. signifying
   hypothetical or non-existent; in the fifth column the percentage
   ionization of the acid in 0.1 N solution — if no exact figure can
   be found specify whether very weak, weak, or strong.


2. Give the names of the oxides having the formulas N 2 O, NO,
   NO 2 , C1O 2. Give a brief account of the properties of each, includ-
   ing state of aggregation, stability, ability to support combustion,
   behavior with water.