Abstract
By using a difference in behaviours of ammonium salts and potassium salts in mixed solvents of wateralcohols or water-acetone, an alkalimetric titration of ammonium salts with aqueous potassium hydroxide solution as the titrant was presented.
The apparent pH value of an aqueous solution of a salt was increased by mixing organic solvents, among which acetone was most effective. Comparing potassium salt and ammonium salt, the former was much influenced in increasing pH.
The titration of ammonium salts was done in solutions containing about 60% (v/v) of acetone, and titration curves very similar to ordinary weak acid-strong base titration curves were obtained.
A mixed indicator of phenolphthalein and bromophenol blue was useful. The concentration of free acid in an ammonium salt solution was also determined by an inspection of the titration curve.
