资源描述：
《EDTA滴定液的配置与标定》由会员上传分享，免费在线阅读，更多相关内容在工程资料-天天文库。
1、EDTA滴定液的配置与标定I.purpose1.understandtheprincipleofEDTAstandardsolutioncalibration.2.mastermethodsforpreparingandcalibratingEDTABstandardsolutions.Two,principleEDTAtwosodiumsalt(customarilycalledEDTA)isanorganiccomplexingagentthatcanformastable1-1chelatewithmostmetalionsandi
2、softenusedasthestandardsolutionforComplexometrictitration・ThesolubilityofEDTAinwateris120g/L,anditcanbemixedintoasolutionwithconcentrationbelow0.3mol/L・EDTAstandardsolutionisusuallynotpreparedbydirectmethod,butisfirstpreparedintoroughlyconcentratedsolution,andthencalibrat
3、ed.ThestandardreagentsusedtocalibrateEDTAstandardsolutionsaremany,suchasZn,ZnO,CaC03,Bi,Cu,MgS04,7H20,Ni,Pbandsoon.WhentheconcentrationofEDTAsolutionwascalibratedwithZincOxideasbasematerial,thechromiumblackTwasusedasindicator,andtheacidityofthetitrationwascontrolledbypH=1
4、0ammoniabuffersolution.Thesolutionwaschangedfrompurpletopureblue,whichwastheendpoint・Threereagents1.EDTAtwosodiumsalt(EDTA).2.ammoniaammoniumchloridebuffer(pH二10):take5.4Gammoniumchloride,addsomewatertodissolve,add35mLammoniawater,andthendiluteittolOOmLwater・3.chromiumbla
5、ckTindicator:take0.lgchromiumblackT,addlOg,sodiumchloride,grindingandmixing・4.40%ammoniasolution:take40mLammoniawateranddilutewithwatertolOOmL・5.ZincOxide(benchmarkreagent)・6.hydrochloricacidFourstepsPreparationof1.0.OlmolL-1EDTAsolutionTaketheEDTAtwosodiumsalt(Na2H2Y.2H2
6、0)4G,addlOOOmLwater,heatittodissolve,shakeitaftercooling,suchasturbidity,shouldbeusedafterfiltration.Putinglassbottle,avoidcontactwithrubberstopperandrubbertube・Labe1.Preparationof2.zincstandardsolutionAccuratesaidbenchmarkZnOtakeabout0.16gat800DEGCtoconstantburning,place
7、dinasmallbeaker,add0.4mLofhydrochloricacid,dissolvedinto200mLvolumetricflask,dilutewithwatertovolume,andmix.Calibrationof3.EDTAsolutionconcentrationDraw30.00~35.0OmLzincstandardsolutioninto250mLconicalflask,add70mLofwater,with40%ammonianeutralizationtopH7"8,pluslOmLammoni
8、aammoniumchloridebuffersolution(pH二10),addalittlechromeblackTindicator,withgoodEDTAsolutiontitra
