A precise method for determining the chlorine content in soluble chloride by the EDTA titration

This paper relates to the principle and condition of a precise method for determining the chlorine content in water soluble chloride by EDTA titration.After the sample was dissolved,the Cl- was deposited by using AgNO3 solution in a strongly acidic medium.After this deposit was filtered,a displacement reaction took place following the addition of excess Ni(CN)2-4 ions.In an ammoniacal buffer solution with a pH value of 9.5,the displaced Ni2+ ions were titrated by standard EDTA solution to the end point using murexide as the indicator.The result showed that the improved method had been proved to be accurate,less disturbed and effective for end point determination.It was an accurate method for determination of chlorine content.The relative standard deviation of the analytical results was 0.18%,and the recovery rate of add standard was 98.3%～100.9%.