﻿MERCUROIJS PERCHLORATE VOLTAMETER 49 



Hg, Cu AND Ag Voltameters est Series. 



Exp. 

 Is 0. 



Car- 

 reat. 



Wt. A? 

 Deposited. 



Wt. Cu 



Deposited. 



Wt. Cu C>il- 

 culated 

 from Ag. 



Error. 



Wt. Hg 



Deposited. 



Wt. II g 



Calculated 

 from Ag. 



% 

 Error. 



13B 

 14 A 

 14B 



0.85 

 0.50 

 0.50 



5.0711 

 4.1451 

 4.1451 



1.4936 

 1.2227 

 1.2227 



1.4941 

 1.2213 

 1.2213 



-0.03 

 + 0.11 

 +0.11 



9.4848 

 7.6707 

 7.6308 



9.3970 

 7 7003 

 7.7003 



+ 0.40 

 -0.38 

 -0.12 



The conditions for the above experiments were : 

 Anode area was about 3.14 sq. cm. 

 Cathode area was about 7 sq. cm. 



Distance between anode and cathode was about 2.5 cm. 

 Volume of the electrolyte was about 35 cc. 



Composition of the electrolyte was : 0.6420 gm. HgClO^ per cc, 

 0.2836 gm.. HCIO^ per cc, and 0.04 gm. NaClO^ per cc 



Changes in temperature during the course of the experiment 

 affect the accuracy of the results. The electrolyte should be at the 

 same temperature when readings are taken before and after electrol- 

 ysis. When the electrolyte is heated by the current, it should 

 either be allowed to regain its original temperature before reading, 

 or a correction should be made for the thermal expansion of the 

 amount of mercury in the reservoir. 



The advantages of the mercuroiis perchlorate voltameter are : 



1. A very high current density may be used. 



2. Mercurous perchlorate is very soluble in water and the solu- 

 tions, thus formed, are entirely free from, any decomposition or pre- 

 cipitation of basic salt. 



3. The amount of metal deposited, being a liquid, may be very 

 rapidly determined by measurement rather than by weighing. 



4. Equivalent quantities of electricity deposit from two to six 

 times greater weight of mercurous mercury than of any other metal 

 This gives greater accuracy. 



5. The deposited metal on the cathode is in such form that it 

 may be transferred to the anode for further use without any other 

 treatment. 



