﻿PREPARATION OF PER CHLORIC ACID 



27 



Commercial barium perchlorate was used. The material was 

 "caked" in the bottle and an average sample was difficult to obtain. 

 An analysis showed 53.5 per cent of ClO^. The C. P. hydrochloric 

 acid which was used showed a specific gravity (spindle) of 1.16 at 

 24°. The commercial acid which was used in one experiment had 

 a specific gravity of 1.14 at 24°, and each cc. contained 0.00097 

 gram of non-volatile matter. 



Table I.— Effect of Water. 



The sodium perchlorate (20 grams) was dissolved in 7cc. of water at 105° and 

 then 20 cc. concentrated hydrochloric acid were added. For comparison the results 

 without water are included in this table. 



Gram s 

 water 

 added. 

 Cc. 



HCIO4 in 

 In terms 



the filtrate, 

 ot* NaCl()4. 



NaClO^. in 

 filtrate. 

 Grams. 



Total CIO4 in filtrate. 

 In terms of NaClOi. 



NaClO^ 

 in NaCl 

 residue. 

 Grams. 



Grams. 



A ^ 



Per cent. 



Grams. Per cent. 



7.0 



15.48 



81.6 



2.63 



18.11 94.7 



0.2 



0.0 



10.97 



88.4 



1.65 



18.62 97.4 



0.46 



The above results show that water should not be added. 

 Table II.— Effect of the Quaxtity of Hydrochloric Acid. 





HCIO4 in the filtrate. 

 In terms of NaiJlO^. 



A 



NaHlO* 

 in filtrate. 

 Grams. 



Total CIO4 in filtrate. 

 In terms of NaCl()4. 



NaClO^ 

 in Na(^l 

 residue. 

 Grams. 



Cc. of HCl. 



/ 



Grams. 



Per cent. 



Grams. 



Per cent. 



10 



13.65 



71.4 



1.91 



15.56 



81.4 



2.72 



15 



15.4 



80.5 



1.61 



17.05 



89.2 



3.46 



20 



16.97 



88.4 



1.65 



18.62 



97.4 



0.46 



25 



18.13 



94.8 



0.84 



18.97 



99.2 



0.2 



30 



18.35 



96.0 



0.79 



19.14 



100.1 



0.18 



50 



18.65 



97.6 



0.63 



10.28 



100.8 



0.34 



This table shows that 25 to 30 cc. of hydrochloric acid should be 

 used for each 20 grams of sodium perchlorate. 



Table III. — To Find the Temperature Needed to Expel the Hydrochlo- 

 ric Acid from the Filtrate. 



CI in the filtrate. 

 In terms of NaC104. 

 Temperature. Grams. 



120° 2.006 



130° 0.06 



135° 0.0 



145° White fumes of HCIO4. 



The filtrates containing the perchloric and hydrochloric acids 

 were heated upon a hot plate. The sides of the beaker should be 

 brought to the temperature of the experiment since, otherwise, the 

 drops of the liquid which condense upon the upper part of the 

 beaker retain hydrochloric acid. When the temperature of the 

 entire beaker was brought to 135° there was insufficient hydrochloric 



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