[archib.\ld-piguet] ELECTROLYTIC DEPOSITION OF IRON 111 



about the cathode and anode, before and after electrolysis, partic- 

 ularly as regards their acidity. For this purpose a solution of ferric 

 chloride in pure acetone was prepared and a part of it electrolysed for 

 96 hours in an H tube. A second part was allowed to stand for the 

 same length of time and then titrated with NaOH solution. Portions 

 were taken from about the cathode and anode and examined in the 

 same way. The results were as follows: — ■ 



The standard solution of sodium hydroxide used contained 

 0-0565 gram of NaOH in 10.00 cc. of solution. 



10 cc. of solution not electrolysed required 1 • 14 cc. of NaOH 

 solution for neutralization 



10 cc. cathode solution after electrolysis required 1-06 cc. NaOH 



10 cc. anode solution after electrolysis required 2- 10 cc. NaOH 



In a second experiment the electrolysis was carried on for only 

 20 hours, the solution being the same as before. 



10 cc. of solution not electrolysed required 1 • 14 cc. NaOH 



10 cc. of solution about cathode after electrolysis required 1 -OOcc. 

 NaOH 



10 cc. of solution about anode after electrolysis required 2-16 cc. 

 NaOH. 



The solution about cathode gave no test for Fe"^"^ ions. 



In making the titrations it was found that methyl orange gave 

 the best results as an indicator. Acetone decolourizes phenolph- 

 thalein, while with alizarine red a poor end point was obtained. Work- 

 ing carefully, a satisfactory end can be obtained with methyl orange. 



A further experiment was carried out with a solution consisting 

 of 75% acetone, 25% water and 0-1500 grams FeCh. After elec- 

 trolysing the solution in the H tube for 20 hours the acidity in both 

 the anode and cathode compartments was measured. 



10 cc. of solution not electrolysed required 1-05 cc. NaOH 

 solution. 



10 cc. of cathode solution after electrolysis required 0-80 cc. 

 NaOH solution. 



10 cc. of anode solution after electrolysis required 1 • 27 cc. NaOH 

 solution. 



A test was also made for the presence of formaldehyde. Acetone 

 interferes with practically all of the color reactions used for detecting 

 formaldehyde, however, it was found that the gallic acid — alcohol — 

 sulphuric acid test could be used with satisfaction; acetone giving a 

 red colour, while the presence of aldehyde is shown by the formation 

 of a green ring at the junction of the two liquids. No formaldehyde 

 was found. 



