Electro-chemistry : by Lehfeldt Robert Alfred 1868-1927 & Moore T. S

Author:Lehfeldt, Robert Alfred, 1868-1927 & Moore, T. S
Language: eng
Format: epub
Tags: Electrochemistry
Publisher: London : Longmans, Green
Published: 1908-03-25T05:00:00+00:00

§ 4. DOUBLE AND COMPLEX SALTS.

Hittorf, 1 from his work on the transport numbers for salts, divided double salts into two classes: (i) those which ionise simply, i.e. behave as ordinary salts, and (2) those which. split up into the ions of the salts of which they are composed, i.e. behave in solution as mixtures of the salts from which they are formed. After Ostwald, the salts of the first class are called complex salts, and the name " double salts " is reserved for those of the second class.

It is easy to distinguish the two classes by means of ordinary chemical reactions. Thus, a solution of potassium ferrous sulphate gives the reactions of the ions K", Fe", and SO 4 ", but a solution of potassium ferrocyanide gives no reaction for Fe" or CN', but only for K f and a complex ion (FeCeN 6 )"".

Examples of complex salts are —

K 3 FeC 6 N 6 , KAg(CN) 2 , (NH 4 ) 3 Fe(C 2 O 4 ) 3 , K, 2 PtCl 6 Examples of double salts are —

K 2 S0 4 ,MgS0 4 6H 2 0, K 2 S0 4 ,A1 2 (S0 4 ) 3 2 4 H 2 0

Later work has, however, shown that the distinction between complex and double salts is one of degree and not of kind.

The electrical conductivity of a mixture of solutions of two salts can be calculated from the conductivities of the separate solutions, if no reaction occurs between the salts or their ions. On mixing solutions of two salts which together form a complex salt, a reaction takes place — the formation of complex from simple ions — and the conductivity becomes less than that calculated. But a mixture of solutions of two salts which together form a double salt should give the calculated conductivity, since, according to the definition of double salts, no reaction should take place. Now, it has been found 2 for

1 Pogg. /*««., 106. 513(1859).

2 Jones and Mackay, Amcr. C/iem.Jour., 19. p. 83.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.