ACIDS 85(b) Solutions of Electrolytes. Test for conductivity each of
the following solutions: Crush about 0.3 gram of each of the solid
salts tested in (a) to a powder and dissolve each in 10 cc. of water.
Add 10 drops of glacial acetic acid to 10 cc. of water. Dilute 2
cc. of each of the laboratory acids (which are already in solution
in water) with 10 cc. of water. Dissolve about 0.3 gram each of
sodium hydroxide and potassium hydroxide in 10 cc. of water.
Dilute 2 cc. of ammonium hydroxide solution with 10 cc. of water.
List the above solutions in the order of their conductivity.
What classes of substances conduct when in solution? What ex-
planation can you give of electrolytic conductance, and how can
you account for the fact that some solutions conduct much better
than others?
(c) Solutions of Non-Electrolytes. Dissolve 0.5 gram of cane
sugar, 0.5 gram of urea, 0.5 cc. of alcohol, 0.5 cc. of glycerine each
in 10 cc. of water, and test the conductivity of the solutions.
ACIDS- Test the conductivity of pure tartaric acid (a solid) and of
pure acetic acid (glacial acetic acid).
Then test the conductivity of these same acids dissolved in
10 to 20 parts of water, and also of other common laboratory acids
diluted with water.
Look up the percentage of ionization in 0.1 N solution (table
on page 100) of each of the acids. What component is common to
all acids and is responsible for the characteristic properties of
acids? Name the other components (i.e., species of ions or mole-
cules) in any acid solution. - Strong and Weak Acids. In order to compare the strength
of acids it is necessary to have solutions of the same concentra-
tion. Prepare 50 cc. each of 0.1 N hydrochloric and acetic acids
by diluting 5 cc. of IN acid with 45 cc. water. Carefully com-
pare the conductivity of these 0.1 N acids, using electrodes B.
Carefully compare the intensity of the sour or acid taste,* but do not
swallow any of the acid. Rinse out the mouth with water. Quite
a bit of experimenting is necessary to find just the amount of acid
- Since a chemist should be familiar with the taste of hydrogen and hy-
droxyl ions, we have set the very bad precedent here of giving directions to
taste the dilute solutions of acids and bases. In no other case should any
laboratory chemical be taken in the mouth.