Synthetic Inorganic Chemistry

POTASSIUM NITRATE^55

procedure and answer the following questions based on the flow
sheet. For the purposes of the calculations one will have to
assume that in every nitration a perfect separation of solution from
crystals is obtained — a condition which obviously is not realized
in practice.

FLOW SHEET

Heat in a covered casserole 170 grams of NaNOa, 149 grams of KC1, and 210 cc of water Boil

the mixture 1 minute and then filter hot Do not rinse out the casserole but use it for the second

boiling

On Filter

NaCl, dirt, and

some KNO3

Transfer to cas

serole in which

first boiling

was made

U)

Filtrate (B) Cool to 10° and filter

On Filter

Crystals of

KNO3 impure

Press and wash

with 20 cc ice-

cold water

(C)

Filtrate (D) Saturated with KNO3 and NaCL Pour it

into original casserole containing impure NaCl (A) Boil

5 minutes Filter hot

On Filter

NaCl dirt and a

little KNOs

Save tempora-

rily

(E)

Filtrate Cool to 10° and filter

On Filter

KNOs impure

Press and wash

with ice - cold

water

(F)

Filtrate Saturated

with KNO3 and

NaCl Savetem

poranly in flask

labelled "mother

liquors "

«?)

Y
RECBYSTALLIZATION
Unite the two lots of moist impure KNO3, add half their weight of distilled water, and heat
until solution is complete Cool to 10° and filter, pressing out as much as possible of the liquid
Stop suction Pour 15 cc ice cold distilled water over the crystals and let it permeate the mass
Apply suction and pressure Test for chloride If any is found repeat the washing process until
the product is free from chloride Add all filtrates to the mother liquors, G

1. What weight of KN0 3 will be dissolved in the hot nitrate


2. What weight of NaCl will be dissolved in the hot nitrate


3. What weight of solid KN0 3 will separate when the nitrate
   (B) is cooled to 10° (C)?


4. What weight of solid NaCl will be obtained together with
   the KN0 3 in (C)?


5. Assume that boiling the nitrate (D) after adding (A) re-
   duces the amount of water to 150 grams; how many grams of
   NaCl will be left on filter (E) after filtering at 100°?