Action of Hydrated and Nonhydrated Salts on Saponification. 93 



To see if the addition of salts would have any effect on the titration, 

 we titrated in the presence of the ester and a salt : 



10 c.c. acetic acid, strength unknown: 



In presence of the ester and calcium chloride; 9.05 c.c. of base used. 

 In presence of the ester and potassium chloride; 9.0 c.c. of base used. 



Ammonium hydroxide and alcoholic corallin are, then, the base and 

 the indicator to be used. 



At first one-fifth normal ammonia was used, but this gave us such 

 small volumes that we decided to use one-twentieth normal. 



After preparing the solution of the base, it was found to be not quite 

 one-twentieth normal, but to contain 0.00167732 gram per c.c. 



For use with the methyl formate a fifth-normal solution was made up 

 which contained 0.007 gram per c.c. 



To see if the methods we were using were accurate, the following 

 experiments were carried out : 



0.0733 gram of glacial acetic acid was weighed out and titrated with 

 ammonia, corallin being used as the indicator. The amount of acetic 

 acid calculated from the titration was 0.0730 gram. We would then 

 have an error of less than 0.5 per cent. With other organic acids we 

 found errors of less than 0.1 per cent. 



The results obtained with formic acid of about 98.5 per cent purity 

 were 0.4917 gram weighed out, and 0.4842 gram was calculated from the 

 titration, giving us an error of about 0.1 per cent. 



METHOD OF PROCEDURE. 



Solutions of the salts and the ester were measured into bottles, 

 which were then placed in the baths. After the required time had 

 elapsed, the bottles were removed from the baths, and their contents 

 titrated against the standard base. We found, after a good deal of 

 preliminary experimenting, that the most favorable conditions for 

 work were: for the methyl acetate, 4 c.c. of the ester to 30 c.c. of water, 

 24 and 48 hours, 15, 25, and 35 degrees, and normal, half -normal, and 

 quarter-normal salt solutions. For the methyl formate, 2 c.c. of the 

 ester to 30 c.c. of water, 4 and 8 hours, 15 and 25 degrees (b. p. of 

 methyl formate 32.3) and the same concentrations of the salts as 

 were used with the methyl acetate. The bottles, when taken out of 

 the baths, were immediately chilled to retard the reaction. The time 

 required for titrating was practically the same as that for adding 

 the ester; therefore, the results are comparable. 12 solutions were 

 studied at a time, 6 being duplicates; 2 bottles containing pure water 

 and ester were included in the sets of 12 bottles, to act as standards 

 and to show that the conditions did not vary. The addition of the 

 ester and the titration of the contents of the bottles were always 

 carried on in the same order; e. g., the bottle to which the ester was 

 added was titrated first. The methyl formate had to be measured at 



