电位滴定法测定镀黑铬溶液中硝酸钠含量  

Determination of the content of sodium nitrate in black chromium plating solution by potentiometric titration method

作　　者：马春华[1] 

机构地区：[1]武夷学院化学与环境工程系绿色化工重点实验室,福建武夷山354300

出　　处：《电镀与涂饰》2008年第8期26-27,共2页Electroplating & Finishing

基　　金：福建省教育厅资助项目(JB07185);武夷学院资助项目(XQL07005)

摘　　要：介绍了一种用于测定镀黑铬溶液中NaNO3含量的电位滴定方法。硝酸根离子在热的浓硫酸中以氯化钠为催化剂，与硫酸亚铁铵反应，过量的亚铁离子以重铬酸钾标准溶液进行电位滴定，硝酸钠的含量根据加入的硫酸亚铁铵溶液的体积和消耗的重铬酸钾溶液的体积之差进行计算。该方法能自动控制滴定过程，终点判断准确，重现性好，回收率为98．21％～102．45％，相对标准偏差为0．79％。A potentiometric titration method for determining the content of NaNO3 in black chromium plating solution was introduced. It is based on the reaction of NO3 with （NH4）2Fe（SO4）2 in hot concentrated H2SO4 using NaCl as catalyst and the titration of excess Fe^2＋ with standard K2Cr2O7 by potentiometry. The content of NaNO3 is calculated by the difference between the amounts of （NH4）2Fe（SO4）2 added and K2Cr2O7 consumed. The method features automatic control of titration process, accurate determination of endpoint and good reproducibility, having a recovery of 98.21%- 102.45% and a RSD of 0.79%.

关 键 词：镀黑铬 硝酸钠 电位滴定 

分 类 号：O655.2[理学—分析化学]