Phelps and Weed— Acids and Acid Anhydrides. 141 



filtered off and recrystallized out of boiling water. The pure 

 malonic acid was then allowed to come to constant weight 

 over sulphuric acid in a desiccator. 



To obtain pure benzoic acid, benzoic ester was treated with 

 sodium hydroxide in excess, and acidified with hydrochloric 

 acid. The benzoic acid thus precipitated was crystallized twice 

 from water and dried to constant weight in a desiccator over 

 sulphuric acid. 



Table III. 







HC1 value 



HC1 value 



Theory 



Error 





Benzoic 



of NaOH 



of Ba0 2 Ho 



in terms 



in terms 



Xo. 



acid 



used 



used 



of HC1 



of HC1 





grin. 



grin. 



grin. 



grin. 



grm. 



I 



0-2000 



0-0598 





0-0597 



•0001 + 



II 



0-2000 



0-0599 







0-0597 



•0002 + 



III 



0-2000 



0-0597 



. 



0-0597 



•0000 + 



IV 



0-2000 



0-0598 







0-0597 



•0001 + 



Y 



0-2000 



_ 



0-0598 



0-0597 



•0001 + 



VI 



0-2000 







0-0597 



0-0597 



•0000 + 



YII 



0-2000 







0-0597 



0-0597 



■0000 + 



All 



0-2000 







0-0597 



0-0597 



•0000 + 



In all of the experiments in Table III, alkali in amount nearly 

 sufficient to neutralize the acid was run into the flask, which 

 was then heated. This aided materially in securing the solu- 

 tion of the benzoic acid in the water and did not necessitate 



raising 



the solut 



ion to th< 



3 boiling 



point. 













Table IV. 













HC1 



HC1 



Theory 



Error 







Phthalic 



value of 



value of 



in terms 



in terms 





Phthalic 



anhy- 



XaOH 



Ba0 2 H 2 



of 



of 



Xo. 



acid 



dride 



used 



used 



HC1 



HC1 





grm. 



grm. 



grm. 



grm. 



grm. 



grm. 



1 



2000 







0-0880 







0-0878 



■0002 + 



11 



0-2000 







0-0880 







0-0878 



0002 + 



III 



0*2000 







0-0879 







0-0878 



•0001 + 



IV 



0-2000 







0-0878 







0-0878 



•0000 + 



V 



02000 











0-0876 



0-0878 



'0002 — 



VI 



0-2000 











0-0877 



0-0878 



•0001 — 



YII 



0-2000 











0-0878 



0-0878 



•0000 + 



Till 



0-2000 











0-0879 



0-0878 



•0001 + 



IX 







0-2000 



0-0986 







0-0985 



0001 + 



X 







0-2000 



0-0985 







0-0985 



•0000 + 



XI 







0-2000 



0-0986 





0-0985 



0001 + 



XII 







0-2000 



0-0987 



. 



0-0985 



0002 + 



XIII 







0-2000 







0-0986 



0-0985 



0001 + 



X1Y 







0-2000 







0-0985 



0-0985 



0000 + 



XV 







0-2000 







0-0986 



0-0985 



0001 + 



XYI 







0-2000 



_ . 



0-0987 



0-0985 



0002 + 



