288 Linhart — Hydrolysis of Alky I Metallic Sulphates. 



done in the cold (room temperature), the excess of sodium 

 hydroxide was neutralized with hydrochloric acid and made 

 slightly acid. The barium sulphate precipitated under these 

 conditions carried down considerable sodium chloride. In 

 order to remove as far as possible this included sodium chlor- 

 ide, the precipitated barium sulphate was filtered through an 

 ignited and weighed perforated platinum crucible, thoroughly 

 washed with hot water and then ignited. After cooling the 

 precipitate was again washed with hot water until the wash- 

 water no longer reacted with silver nitrate. The ignition was 

 then repeated and the barium sulphate again washed with hot 

 water after cooling. In this manner, practically all the sodium 

 chloride was removed. The crucible was then heated to red- 

 ness, allowed to cool and weighed. The barium sulphate 

 resulting was used in calculating the velocity constants in place 

 of sodium sulphate, since this weight calculated to gram 

 equivalents per liter is exactly equivalent to the sodium sul- 

 phate resulting from the saponification. 



The saponification of the barium and strontium esters with 

 barium hydroxide was carried out in glass tubes. In these 

 cases it was found that, although the barium hydroxide began 

 at first to attack the glass, a thin film of barium sulphate or 

 silicate or probably of both was formed on the walls of the 

 tubes, thus preventing further corrosion. In these experi- 

 ments, as in the above, the barium hydroxide was neutralized 

 with hydrochloric acid in slight excess, and the precipitated 

 barium sulphate was thoroughly mixed to decompose any 

 barium hydroxide that might have adhered to the precipitate. 

 The precipitate was then treated and estimated in the manner 

 described above. 



Experimental Results. 



T = 60° 

 Ethyl sodium sulphate 0'3 grm. equiv. perl. — B 

 Sodium hydroxide 1-35 " " " 1. = A 



BaS0 4 = x 



t , ' . K* Kf 



in grm. 

 in hours in grams equiv. 1st order 2d order 



200*0 0*2564 0'1099 0*00242 0-00211 



603-0 0-6100 0-2614 0*00±90 0'00208 



986-0 0-8400 0'3600 0-00186 0*00209 



oo 1*4004 0*6000 



Methyl strontium sulphate 0*3057 grm. equiv. per 1. = A 

 Barium hydroxide 0*2757 " " " 1. = B 



* See page 285. \ See page 287. 



