solution by at least six runs against 7-8 gram samples of potassium acid 

 phthalate, titrating to a faint pink with phenolphthalein. 

 Tenth Normal Sodium Hydroxide : 



The procedure is the same as for normal sodium hydroxide, except 

 that 6 ml. of the saturated sodium hydroxide solution is used per liter 

 of solution, and 0.8-0.9 gram samples of potassium acid phthalate are used. 

 Normal Hydrochloric Acid : 



For each liter of normal hydrochloric acid, dilute 86 ml. of the 

 concentrated acid, sp. gr. 1.18, to one liter with distilled water. Adjust 

 as closely as possible to one normal by titration with the standardized 

 one normal sodium hydroxide. Finally, accurately standardize the acid 

 by at least six titrations with 40-45 ml. samples of the standard base, 

 to a faint pink with phenolphthalein. 

 Tenth Normal Hydrochloric Acid: 



The procedure is the same as for normal hydrochloric acid, except 

 that 8.6 ml. of concentrated acid, sp. gr. 1.18, is used per liter of 

 solution, and the standard tenth normal sodium hydroxide is used in the 

 titrations . 

 Normal Sulfuric Acid: 



For each liter of normal sulfuric acid, slowly add 27 ml. of con- 

 centrated sulfuric acid, sp. gr. 1.84, to about 250 ml. of distilled 



water, allow to cool, and dilute to one liter. Proceed as with normal 



hydrochloric acid. 



Tenth Normal Sulfuric Acid : 



Proceed as for normal sulfuric acid, using 2.7 ml. of concentrated 

 sulfuric acid, sp. gr. 1.84, per liter of solution. Standardize with 

 tenth normal sodium hydroxide. 

 Normal Acetic Acid: 



For each liter of normal acetic acid, dilute 60 ml. of glacial 

 acetic acid to one liter with distilled water. Proceed as with normal 

 hydrochloric acid. 

 B. Other Standard Solutions : 

 Tenth Normal Potassium lodate : 



Weigh out 3.5672 grams of dried potassium iodate and make up to 

 one liter with distilled water. This solution keeps very well and need 

 not be freshly prepared each year. 

 Tenth Normal Sodium Thiosulfate : 



For each liter of solution, dissolve 24.8 grams of hydrated sodium 

 thiosulfate, Na2S203» 5H2O, in freshly boiled disti lied ^ater , add 10 ml. 

 of tenth normal sodium hydroxide, and dilute to one liter. To standardize 



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