BARIUM PEROXIDE 141Apparatus: 8-inch porcelain dish.
5-inch funnel.
2-liter common bottle.
600-cc. beaker,
suction filter and trap bottle,
mortar and pestle.
Bunsen burner,
iron ring and ring stand.Procedure: Dissolve the barium hydroxide in 500 cc. of warm
water and pour through a filter, without suction, into a 2-liter
bottle. Add 1 liter of cold water.
While the filter is draining place the HC1, 250 cc. ice water, and
about 100 grams ice in an 8-inch porcelain dish. Grind the BaO 2
in a mortar with water until a smooth uniform paste is obtained
and add enough water to make 100 cc. Add the BaC>2 suspension,
a little at a time, with constant stirring, to the cold HC1 solution
until the BaO 2 ceases to dissolve. Then add the remainder of
the BaC>2 suspension all at once and stir until the suspension has
turned brown due to the precipitation of Fe (OH) 3. Then filter the
solution without suction into a 600-cc. beaker.
Pour, in a thin stream, with constant stirring, the hydrogen
peroxide solution into the barium hydroxide solution in the 2-liter
bottle. Let the flaky barium peroxide hydrate settle and then
collect it on a suction filter. As soon as the water is drawn out,
shut off the suction, wash with 15 cc. cold water, press the solid
into a compact cake, and again suck dry. Do not draw any
quantity of air through the product. Wrap the crystals in paper
towels and dry them according to Note 9 (6), page 15. Preserve
the product in a 4-ounce cork-stoppered bottle.
QUESTIONS- Explain why barium chloride would not give a precipitate
with hydrogen peroxide. - The hydrogen peroxide solution obtained as an intermediate
product in this preparation contained barium chloride. Suggest
with what reagent one might treat the purified barium peroxide
hydrate to obtain a pure solution of hydrogen peroxide. Give
explanation.