QUANTITATIVE DETERMINATIONS
TABLE III.—CONVERSION TABLE FOR SPECIFIC GRAVITIES

57

Specific gravity*
Per cent, HC1
Specific gravity*
Per cent, HCl

1.000
0.16
1.115
22.86

1.005
1.15
1.120
23.82

1.010
2.14
1.125
24.78

1.015
3.12
1.130
25.75

1.020
4.13
1.135
26.70

1.025
5.15
1.140
27.66

1.030
6.15
1.142
28.14

1.035
7.15
1.145
28.61

1.040
8.16
1.150
29.57

1.045
9.16
1.152
29.95

1.050
10.17
1.155
30.55

1.055
11.18
1.160
31.52

1.060
12.19
1.163
32.10

1.065
13.19
1.165
32.49

1.070
14.17
1.170
33.46

1.075
15.16
1.171
33.65

1.080
16.15
1.175
34.42

1.085
17.13
1.180
35.49

1.090
18.11
1.185
36.31

1.095
19.06
1.190
37.23

1.100
20.01
1.195
38.16

1.105
20.97
1.200
39.11

1.110
21.92

I ,:

* At 15°.

In carrying out the dilution the required amount of acid is measured in a
dry volumetric flask. This is then poured into a 1000-cc volumetric flask,
the smaller flask being rinsed several times with distilled water and the
rinsings added to the solution in the larger flask. Dilute to the base of the
neck of the 1000-cc flask and mix; finally dilute to the mark and mix
thoroughly.
Sodium Carbonate.—The sodium carbonate to be used as a standard is
best made from sodium bicarbonate, as this salt can usually be obtained in a
high state of purity, so far as other interfering solids are concerned, the only
impurities being water and normal sodium carbonate. By heating to about
300° the following reaction is produced:
2NaHCO3 -> Na2CO8 + H20 + CO2.
At the same time water of crystallization is expelled and pure dry sodium
carbonate remains.