Asxew.—Solubility and Hydrolysis of Calcium Carbonate. 793 
water in circulation. The solution-vessels with their stirrers were supported 
in the bath. The pulleys from the stirrers were connected by means of 
solid rubber belting with a central pulley, which in turn connected with 
crystals and 250 c.c. of salt solution (freshly made from gas-free water). 
The contents were kept stirred at a rate sufficiently high to keep the 
carbonate in suspension. The solutions were left for several days, the period 
depending on the concentration of the salt solution ; the period was deter- 
mined by a series of experiments, sodium chloride being taken as standard. 
The calcium in solution was estimated as oxide or sulphate. 
The effect of traces of carbon dioxide is very considerable, since ordinary 
distilled water gave a much larger value than the freshly boiled water: for 
example— 
Ordinary distilled water .. 196 x 10-5 grm. mols. per litre. 
Gas-free water .. 35 ... 134 x 1075 grm. mols. per litre. 
and also with sodium-chloride solutions. The figures are—Gram molecules 
of carbonate per litre X 
и мг Ис M M M М M 
ConcentrationotNaCL.B0. 100. 150 :900 400. 500 600 800 1000 
Ordi distilled 
duis Ré 69-8 35:9 321 98-4 222 191 165 161 163 
Gas-free water 52-0 28-6 250 241 179 179 179 161 161 
is i i ini i е of traces 
F this it appears that a slight minimum occurs 1n presence o 
of site dioxide +: about М/800; but this disappears from the second set. 
The following table summarizes the results of the solubility measure- 
ments (gram molecules of carbonate x 10%) :— 
ми xw AM M X EM. M. М M 
— 
“50 100 150 200 600 800 1000 
Nat осо abb HO 1 179 191 161 
МАВ m 3 125 116 
NaBr 409 950 294 205 171 161 15 
y c. s9 wr WO ij 101: re Do 
MO, 9 179 161 161 
78 345 304 286 193 179 
кас ч 15-0 143 
" $820 268 250 241 170 150 з 
КВг ALT 241 21-4 
figures it i imi f curve is obtained 
th it із seen that a similar type o | 
їп coh ae te the effect is not proportional to the Depp ated of the 
salt solution. Sodium chlorate and nitrate give very targe increases 
MEASUREMENT oF HYDROLYSIS. 
ination hydroxyl ions was 
nstant method for the determination 1 ions 
a this case, so recourse was had to electromotive force 
gr paeem of the electromotive force developed ” : cell оле 
ешш of which contains the — under EE dine ical 
mati ‘ong may be obtained. terminati 
is that F ei atum concentration, but the hydroxyl-ion concen- 
tration is then given by the ation : i 
[8] [ОН] = 1 х 10-“ at 25 ©. 
