DOUBLE DECOMPOSITION

171

therefore
(0K
so that in Fig. 54
^NaN08
,C   N2_^!^!
Na + '-'K)    -        OD2
7Na + CK):AD = Cr>:OD,
or
whence
G-s& + CK is given as dc' by making do'= ad.
Therefore also

1,

(NaN"08)D

B(KC1)

fig. 54-

re

To calculate and represent the separate ionic concentra-
tions we have then :

8C'Na : ^NOS^K = ^NaNOj : ^NOaK == OD2 : OC2
: col =
n,	3CNa: (7Ci(7Na = C|faNo3 : CJaCi = OD2 : OA2.
The first relation leads to (7Na and CK by taking dc'
(Fig- 55) = CNa + CK; then CNaNOs=OD (Fig. 54) is
measured from cx vertically as c'c^; at right angles to it
d^a = CjsTaci = oa (Fig. 54) ; then from d^ the perpen-
dicular d^g on to ac7, and finally ge//tiD. We have then:
ga : ac?! = adx : ao' and grc' : cfdI = c'c?! : c'a,