NEUTRALIZATION 87- Strong and Weak Bases. Repeat in every detail Experiment
4, using sodium hydroxide and ammonium hydroxide as typical
of a strong and a weak base. Make similar tabulations of the
weight of each of the components, (1) water, (2) un-ionized base,
(3) metal radical ion, and (4) hydroxyl ion, in 1 liter of 0.1 N
solution.
NEUTRALIZATION- Neutralization of a Strong Acid and a Strong Base. Fill
a narrow U-tube with 1N hydrochloric acid and insert electrodes
A until the lamp glows dimly but distinctly. Note carefully the
depth to which the electrodes are inserted. Then refill the tube
with liV sodium hydroxide, again insert the electrodes to the
same depth, and notice how strongly the lamp glows.
Run 10 cc. of liV hydrochloric acid into a beaker, add 1 drop
of litmus solution, and then add liV sodium hydroxide until the
color changes to blue. Add a drop or two more acid until the
color again changes, and finally bring the solution to the exact
neutral point when 1 drop of acid will turn the litmus red and a
single drop of base will bring back the blue.
Fill the same U-tube with this neutralized solution, insert the
electrodes to the same depth as before, and compare the conduc-
tivity of the neutral solution with that of the acid and the base.
Explain the process of neutralization according to the ionic
theory, and account for any differences noted in the conductivity.
Write the ionic equation.
Write ionic equations from now on whenever it is possible. Use
the intersecting method as described in Rules 1-8 on page 104.
Do not, however, neglect to give the explanation in words in ad-
dition to the equation. - Neutralization of a Weak Acid and a Weak Base. Test
separately the conductivity of liV acetic acid and of liV am-
monium hydroxide, this time using electrodes B. Neutralize
10 cc. of the liV acid by adding the IN base in the same manner
as in Experiment 7; and compare the conductivity of the neutral-
ized solution with that of the acid and base separately.
Explain the neutralization of a weak acid and a weak base ac-
cording to the ionic theory, and account for the change observed
in the conductivity. Explain why the neutral solution contains
no undissociated molecules of the acid and base.