HYDROGEN ION CONCENTRATION 93
(b) To about 0.2 gram of powdered bismuth oxide, Bi 2 O 3 , in a
dry test tube add 6iV HCl a drop at a time with shaking until the
powder is dissolved. About 12 drops should be necessary. In-
stead of bismuth oxide one may start with basic bismuth nitrate
(Bi(OH) 2 NO 3 or BiONO 3 ). Then add 20 cc. of water to the tube
and mix the contents, observing the white precipitate. Again add
6iV HCl drop by drop with shaking until the precipitate just
redissolves. Then add the solution to 200 cc. of water in a beaker.
The hydrolysis product of the chloride may be a mixture of
BiOHCl 2 , Bi(OH) 2 Cl, Bi(0H) 3. For simplicity consider it all
as Bi(OH) 2 Cl. Write ionic equation for the hydrolysis, and
explain its reversibility.
SOLUBILITY PRODUCT
- Prepare a nearly saturated solution of potassium chlorate
by shaking vigorously about 5 grams of the finely powdered salt
with 15 cc. of water for 5 minutes. Let the undissolved salt
settle and pour off the clear solution, dividing it equally among
three test tubes.
(a) To one portion add about 0.5 gram of solid potassium
chloride.
(6) To a second portion add about 0.5 gram of solid sodium
chlorate.
(c) To a third portion add about 1.5 grams of solid sodium ni-
trate. In each tube agitate the mixture until the added crystals
have dissolved. These crystals can be distinguished from any
finely crystalline precipitate that falls out of the solution.
Tabulate the solubility in formula weights per liter at room tem-
perature of KC10 3 , KC1, NaC10 3 , and NaN0 3.
What is the numerical value of the solubility product of KC10 3?
How many formula weights of KC10 3 could dissolve in a liter of
1.5 formal NaC10 3? How many grams?
HYDROGEN ION CONCENTRATION
- Effect of Its Neutral Salt on the Strength of a Weak Acid.
(a) Methyl orange is an indicator which is used much in the same
way as litmus to show the presence of hydrogen ions. In the
presence of a considerable hydrogen-ion concentration it is pink.
As the hydrogen-ion concentration grows less the color passes
