[ archibald-piguet] electrolytic DEPOSITION OF IRON 109 



cally all the iron had been deposited. A clear solution was obtained 

 in cold dilute sulphuric showing that little if any carbon had been 

 carried down with the deposit. The composition of the precipitate 

 did not correspond to either the formula Fe203 or Fe(0H3). 



Experiment 3. For this solution approximately half a gram of 

 ferric chloride was dissolved in acetone and to this 1 gram of urea was 

 added. This solution was electrolysed with platinum gauze electrodes 

 at a temperature of 25 °C. with a current of 0-02 amperes and a 

 difference of potential of 6 volts. Precipitation was complete after 

 24 hours, in the form of the same red deposit as obtained previously. 

 The precipitate dissolved completely in cold dilute sulphuric acid, 

 no carbon whatever being present. 



Experiment 4. In the case of this experiment the solution was 

 made up of 50 cc. of acetone, 50 cc of water, 0-5 gram of sodium 

 sulphite and the usual amount of iron chloride. The difference of 

 potential between the electrodes was 6 volts. A thin grey film of 

 iron was first brought down which adhered nicely to the cathode. 

 As the electrolysis continued the iron separated out as the same red 

 precipitate obtained before. At the end of fourteen hours all of the 

 iron had been deposited. No carbon was found in the deposit. 



. Experiment 5. A mixture of equal parts of acetone and ethyl 

 alcohol was now employed as solvent, the iron being added in the 

 form of ferric chloride. A current of 0-02 amperes at 5-5 volts was 

 passed through the solution for 24 hours. A dark-red deposit was 

 obtained, blackened by the presence of large amounts of carbon. 

 In order to lower the resistance of the solution, about 1 gram of 

 salicylic acid was added. This had the desired effect as regards the 

 conductivity of the solution, but as the electrolysis continued the 

 solution became dark and large amounts of carbon separated with 

 the iron. 



A solution corresponding to that used above, but to which had 

 been added 5 cc. of cone, hydrochloric acid, was electrolysed for 12 

 hours. This solution conducted the current well but no deposit 

 whatever was obtained. 



Experiment 6. The solution here used corresponded to that of 

 experiment (4) except that no sodium sulphite was added, the solvent 

 being a mixture of equal parts of acetone and water. The difference 

 of potential was 6 volts, while a current of 0-05 amperes was passed 

 through the solution. At the beginning, the iron was deposited as a 

 gray metallic film but on continuing the current over night the red 

 deposit was again brought down, in a form that did not adhere to the 

 electrode. 



