EXPERIMENTS 315Materials: crystallized bismuth nitrate, Bi(NO 3 )3, 5H 2 O, 42
grams = 0.1 F.W.
QN HNO 3 , 10 cc
Na 2 CO 3 solution.
Apparatus: 250-cc. beaker.
2-liter common bottle,
suction filter and trap bottle.
Procedure: Dissolve without heating the crystallized bismuth
nitrate, in 10 cc. of 6 N HN0 3 and 20 cc. of water. Pour this into
2 liters of cold water and stir thoroughly for a few minutes. Let
the precipitate settle completely, and as soon as this has occurred
draw off and save the supernatant liquor; drain the precipitate
on a suction filter, and wash it quickly with about 20 cc. of water.
Dry the precipitate on the steam table, and preserve it as a powder
in a cork-stoppered bottle.
Bismuth Oxide. Combine all the liquors from the foregoing;
add sodium carbonate until alkaline to litmus; let settle, and draw
off the supernatant liquor; boil the remaining suspension after
adding to it about 20 grams more of sodium carbonate. Then
wash the precipitate twice by decantation, drain on a suction
filter, and wash with two or three portions of water. Dry and
preserve this product in a cork-stoppered bottle.
QUESTIONS- In accordance with the above directions, sodium carbonate
is used to precipitate bismuth hydroxide. Why should not the
precipitate be bismuth carbonate? - If this precipitate is not finally boiled with an excess of
sodium carbonate, it is likely to contain a certain amount of basic
nitrate. Explain why this should be so and why the boiling will
convert it completely into the hydroxide.
Experiments
Review in Chapter III the section on the ionization of polybasic
acids, page 116; in Chapter IV, Preparations 8 and 14, and
Experiments 15 and 25; in Chapter VIII, Experiments 11 and 12.
- Oxidation Products of the Elements of Group V. Treat
0.5 gram each of (a) red phosphorus, (6) powdered arsenic,
(c) powdered antimony, and (d) powdered bismuth with