96 EWAN : THE ELECTROLYTIC CONDUCTIVITY X.-Note o n the Electrolytic Conductivity of Fo~rn- an ilide and Thioforrnaiailide. By THOMAS EWAR’, B.Sc., Ph.D. IT was thought possible that the electrolytic conductivity of the aqueous solutions of the amides might throw some light on their structure, and at Dr. Cohen’s request I examined some of them from this point of view. The majority, however, are too sparingly soluble in water to allow of measurements being made, whilst others are de- composed by the water too rapidly. The following numbers were obtained with formnnilide. The measurements were made at 2 5 O , and as rapidly as possible, as the Conductivity increased on standing. p is the molecular conductivity in reciprocal Siemen’s units, pl and refer to two different samples of formanilide which were examined.OF FORMANILIDE AND THIOFORRIANILIDE. 97 Concentration (litres containing 1 gram mol.) v.Pl* pz. Mean p . k x 10 0.026 0.027 04265 5.6 20 0.031 0-034 0.0325 4.2 40 0.040 0.046 0-0430 3.7 80 0.058 0.068 0.0630 3.9 160 - 0.101 0.101 5.1 poo = 355 (approximately). A comparison of the value of 32 above found with its value for- acetic acid (180000 x lO-'O) shows that formanilide possesses only extremely feeble acid properties, and it is not surprising that its sodium salt is, as is shown by the following experiment, decomposed in aqueous solution almost completely into caustic soda and form- anilide. 2 C.C. water and 20 C.C. NllOO NaOH solution weye mixed ; con- ductivity of the mixture = 0.0169. 2 C.C. NjlO formaailide solution and 20 C.C.N/100 NaOH mixed ; conductivity of the mixture = 0.0167. A considerable decrease in the conductivity would have occum-ed if any appreciable quantity of salt had been formed. Thioformanilide, C,H,*NH*CSH, is very slightly soluble in water (the strongest solution obtainable was N/400), and i t decomposes rather rapidly into phenylcarbamine and sulphuretted hydrogen. Its sodium salt appears to exist in aqueous solution. 0.0685' gram of thioformanilide was dissolved in 4 C.C. of 51N/100. NaOH, and the solution made up to 102 C.C. (= N/50). The molecular conductivity of this solution was 180*0 at 25" ; the molecular con- ductivity of N/50 NaOH at 25' = 217.8. The quantity of thioform- anilide taken was equivalent to one quarter of the caustic soda, so that, assuming that the whole of the thioformanilide was converted into sodium salt, and that both it and the caustic sodaare completely dissocinted in N/50 solution, the conductivity of the solution may be calciilated as follows. r = pxa + QpoH + hciH6xs, = 49 + 2.170 + i . 3 5 = 185, The salt decomposes in the same way as the free thioformanilide.