Lab Quimica Analitica DETERMINACIÓN DE CLORUROS MÉTODO DE MOHR

 

[JIPK]_IACA [JIPK]_IAC A JCOIBJCD JCOIB JCD CH]C]IC DC EBDIJC

S[ÅEIOC CJCDÅQIOC ‟ DCMB]C DCM B]CQB]IB QB]IB IJ@B]EK AK DCMB]CQB]IB 0

PBD[EKQ]ÅC WB] W]KOIWIQ W]KOIWI QCOIßJ AKQK]EIJCOIßJ AK ODB][]B_ EÉQBAB AK EBN]  CD[EJB_< -Chuidcr Aikstrc, @rcjf Isrckd

=73077>9

-Hbjzcdks Ebjtkrb, Lksüs Cjarék

=73?7993

- Dkvizcoc Hcrmbzc, @rkay Lbjctncj

=73>710>

- Pidoc ]ceirkz, Fcrbd Cac

=7387=17

Nbrcrib ak prãotioc (aåc y nbrc)< Dujks Dujks 33

=

 

3. IJQ] IJQ]BA BA[O [OOI OIßJ ßJ Kd iÿj odbrurb (Od›), ks ujb ak dbs cjibjks ijbrhãjiobs prijoipcdks kj kd chuc jcturcd y rksia rksiauc ucd. d. Kd ob objt jtkj kjia iab b ak od odbr brur urbs bs ak dcs ch chuc ucss jc jctu turc rcdk dkss sbj sbj vc vcri ricm cmdk dkss y ak akpk pkja jakk  prijoipcdekjtk ak dc jcturcdkzc ak dbs d bs tkrrkjbs ctrcvkscabs, kj oucdquikr ocsb, kstc ocjtiaca sikeprk ks ekjbr quk dc quk sk kjoukjtrc kj dcs chucs rksiaucdks, yc quk kd odbrurb ak sbaib b scd ak eksc (JcOd) (JcOd) ks obeüj kj dc aiktc y pcsc ijcdtkrcab c trcvés akd cpcrct cpcrctb b aihkstivb. aihkstivb. Kd cuekjtb ak odbrurbs kj ujc eukstrc ak chuc pukak tkjkr bråhkjks aivkrsbs. _i sk trctc ak ujc zbjc obstkrc pukak akmkrsk c ij`idtrcoibjks ak chuc akd ecr, kj kd ocsb ak ujc zbjc ãriac kstk cuekjtb sk akmk cd dcvcab ak dbs sukdbs prbauoiab pbr `ukrtks dduvics y kj btrbs ocsbs pukak akmkrsk akmkr sk c dc objtceij objtceijcoiÿj coiÿj akd chuc pbr chucs rksiaucdks, kto. [j objtkjiab kdkvc kdkvcab ab ak odbrurbs pukak acócr dcs objauooibjks y kstruoturcs ektãdiocs y pkrluaiocr kd orkoieikjtb vkhktcd, jb cså kj dcs chucs ak objsueb nuecjb abjak jb rkprkskjtcj eãs ijobjvkjikjtks quk kd hustb hustb akschr akschrcac cacmdk mdk akd chuc, chuc, cakeãs cakeãs ak jb pdcjtkcr pdcjtkcr prbmdke prbmdkecs cs ak pbtcmidi pbtcmidiaca aca.. (Suåeioc Hkjkrcd y Qkojbdÿhioc, Qkojbdÿhioc, =737). Kj kstk ij`brek sk aktkreijcrã dc objokjtrcoiÿj ak odbrurbs ekaicj ekaicjtk tk kd eétbab ak Ebnr kj ujc eukstrc ak chuc jcturcd

BMLKQIPB_< ◂

  Ocdoudcr dc objokjtrcoiÿj objokjtrcoiÿj ebdcr ak dc aisbduoiÿj kstcjacrizcac ak jitrctb ak pdctc.

◂

  Ocdoudcr dc objokjtrcoiÿj objokjtrcoiÿj ak odbrurbs kj ujc eukstrc ak ak chuc jcturcd.

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=. ]KPI_Iß ]KPI_IßJ J AK DIQK]C DIQK]CQ[] Q[]C C ◂

AKQK]EIJCOIßJ AK ODB][]B_ KJ CH[C_ JC JCQ[]CDK_ Q[]CDK_ Kd ibj odbrurb ks ujb ak dbs ibjks eãs ai`ujaiabs kj dcs chucs jcturcdks. Jb sukdk skr uj ibj quk pdcjtkk prbmdkecs ak pbtcmidiaca c dcs chucs ak objsueb, cujquk så quk ks uj ijaiocabr  ak objtceijcoiÿj ak dcs chucs. Kstb ks cså pbrquk, cujquk dc objokjtrcoiÿj ak odbrurb kj chucs chu cs jcturc jcturcdks dks ks euy vcricm vcricmdk dk puks puks akpkja akpkjakk ak dcs ocrcot ocrcotkrå kråstio stiocs cs ak dbs tkrrkjb tkrrkjbss quk ctrcvikscj, aionc objokjtrcoiÿj ks ekjbr obepcrcac obj dc objokjtrcoiÿj akd ibj kj chucs rksiaucdks yc quk dc cotiviaca nuecjc ijorkekjtc jkokscricekjtk aionc objokjtrcoiÿj Dc prkskjoic ak odbrurbs kj dcs chucs jcturcdks sk ctrimuyk c dc aisbduoiÿj ak akpÿsitbs eijkrcdks eijkr cdks ak scd hkec, objtceijcoiÿj objtceijcoiÿj prbvkjikjtk prbvkjikjtk ak aivkrsbs aivkrsbs k`dukjtks k`dukjtks ak dc cotiviaca cotiviaca ijaustricd, chucs kxokakjtcrics ak rikhbs chråobdcs y sbmrk tbab ak dcs eijc ak scdks pbtãsiocs (Octcdcj D.3983, Wkttylbnj, 398=).

[j cdtb objtkjiab ak odbrurbs pukak acócr kstruoturcs ektãdiocs y tcemiéj kvitcr orkoieikjtb ak pdcjtc pdcjtcs. s. Dcs cdt cdtcs cs objokj objokjtrc trcoib oibjks jks ak odbrur odbrurb b kj chucs chucs rksiau rksiaucdk cdks, s, ouc oucjab jab éstcs sbj utidizcacs pcrc kd rikhb kj ocepbs chråobdcs aktkribrc, kj `brec iepbrtcjtk dc ocdiaca akd sukdb. Wbr db tcjtb ks iepbrtcjtk aktkreijcr dc objokjtrcoiÿj ak odbrurbs kj chucs jcturcdks. KJ DC IJA[_Q]IC CDIEKJQC]IC< Kj ujc @ãmrioc ak Wrbauotbs Cdiekjtioibs tikjkj obeb objtrbd ijtkrjb dc aktkreijcoiÿj ak odbrurb ak sbaib ak ocac prbauotb utidizcjab uj eétbab eétba b ak titudcoiÿj hcdvcjbeét hcdvcjbeétrioc, rioc, obj dc `ijcdiaca `ijcdiaca ak cskhurcr cskhurcr quk ksté akjtrb ak dcs kspkoi`iocoibjks ak ocdiaca quk kd objsueiabr akskc, kstk cjãdisis sk rkcdizc kj prbekaib ;77 vkoks c dc skecjc. DC DKONK< Ks ak vitcd iepbrtcjoic kd objtrbd ak ocdiaca kj kstbs cdiekjtbs, dc aktkreijcoiÿj ak odbrurbs, ks ujc ak dcs aktkreijcoibjks eãs iepbrtcjtks pcrc aktkotcr kd chucab kj dkonks yc quk aiseijuyk dc objokjtrcoiÿj ak odbrurbs kj kd prbauotb obj kd cuekjtb ak chuc. Wbr  btrb dcab, sk pukakj kviakjoicr dkonks prbvkjikjtks ak vcocs obj ecstitis, db quk cuekjtc dc objokjtrcoiÿj ak odbrurbs. ◂

KD EÉQBAB AK EBN]  Kd Eétbab Eétbab ak Ebnr Ebnr, ks ujc ak dcs téojiocs téojiocs vbdueé vbdueétri triocs ocs eãs cjtihu cjtihucs, cs, quk ijvbdu ijvbduorc orc dc titudcoiÿj titudc oiÿj ak odbrurbs odbrurbs y mrbeurbs mrbeurbs obj ujc sbduoiÿj sbduoiÿj vcdbrcac vcdbrcac ak jitrctb ak pdctc, kepdkcjab kepdkcjab obeb ijaiocabr orbectb ak pbtcsib. Kd Eétbab kj hkjkrcd ks utidizcab pcrc dc aktkreijcoiÿj

1

 

ak odbrurbs jb sÿdb kj ocjtiacaks rkdctivcekjtk hrcjaks sijb tcemiéj kj ocjtiacaks pkqukócs, obeb dcs objtkjiacs kj kd chuc, kj ouyb cjãdisis sk utidizc. Kstk objsistk objsistk kj ujc titudcoiÿj titudcoiÿj pbr prkoipitcoiÿ prkoipitcoiÿj j c tkepkrcturc tkepkrcturc cemikjtk cemikjtk ak aisbduoibjks aisbduoibjks ak odbrurbs, obj aisbduoiÿj vcdbrcac ak jitrctb ak pdctc 7,3 E, `brecjab uj prkoipitcab mdcjob  pbob sbdumdk ak odbrurb ak pdctc y kepdkcjab obeb ijaiocabr ujc aisbduoiÿj ak orbectb ak  pbtcsib cd ; % e/v. e/v. Kj kd pujtb `ijcd dbs ibjks orbectb rkcooibjcj obj dbs ibjks pdctc `brecjab uj prkoipitcab ak obdbr rblb dcariddb. Dc titudcoiÿj sk ddkvc c ocmb akjtrb ak uj ijtkrvcdb ak pN aktkreijcab. Dc aktkreijcoiÿj ak  odbrurbs pbr kd k d Eétbab ak Ebnr, ks uj

ocsb tåpiob ak ujc prkoipitcoiÿj `rcooibjcac. Dcs rkcooibjks quk sk ddkvcj c ocmb sbj dcs sihuikjtks<

Akmk tkjkr uj pN jkutrb b okrocjb c dc jkutrcdiaca, yc quk si kd pN448 sk aisbdvkråc kd Ch=OrB1 y ai`ioudtcråc dc aktkooiÿj akd pujtb `ijcd ak dc vcdbrcoiÿj y uj pN :: 8 prbvbocråc dc pr prko koip ipitc itcoi oiÿj ÿj ak akdd oc octi tiÿj ÿj Ch+ Ch+ ob obeb eb ChBN ChBN (nia (niarÿ rÿxi xiab ab ak pdct pdctc) c) ak ob obdb dbrr pc pcra rab b y obektkråcebs krrbr. krrbr. Dc koucoiÿj iÿjioc pcrc dc titudcoiÿj akd iÿj odbrurb obj jitrctb ak pdctc ks<

Ch

+

+ JB

()

∝?

+ Jc

()

+

+ Od

()

∝

↝ ChOd

()

+ Jc ()

?. ECQK] ECQK]ICD ICDK_ K_ Y EÉQBA EÉQBAB_ B_ Kstcj stcjac acri rizc zcoi oiÿj ÿj ak Ch ChJB JB?? ³ 7,3 7,377 E Ectkricdks< ◂

  73 Ectrcz Krdkjekykr ak =;7 eD.

◂

  73 Murktc ocdimrcac ak =; b ;7 eD

◂

  Wizktc obj chuc akstidcac.

;

+ ()

+ JB

∝? ()

 

◂

  @kjbd`tcdkåjc.

◂

  Odbrurb ak sbaib quåeiocekjtk purb obeb pctrÿj priecrib.

◂

  _bduoiÿj ijaiocabr ak orbectb ak pbtcsib F=OrB1 F=OrB1 cd ?%. ?%.

◂

  _bduoiÿj _bduoiÿj ak jitrctb jitrctb ak pdctc ChJB? ³ 7.377 7.377 E

◂

  _bduoiÿj ak ãoiab jåtriob, NJB? 7.73 E

◂

  _bduoiÿj ak niarÿxiab ak sbaib, JcBN 7.73 E

◂

  73 mcdcjzc cjcdåtioc.

Ektbabdbhåc< ◂

  Wkscr 7.37 - 7.3; h ak pctrÿj pctrÿj priecrib JcOd

◂

  Qrcjs`krir c uj ectrcz krdkjekykr ak =;7 eD.

◂

  Caioibjcr Caioibjcr chuc akstidcac akstidcac ³ ;7 eD y aisbdvkr aisbdvkr obepdktcekj obepdktcekjtk. tk.

◂

  Ekair kd pN (8 - 37) uscjab dc `kjbd`tcdkåjc obeb ijaiocabr. ijaiocabr.

◂

  Clustcr kd pN kj ocsb ak skr jkokscrib obj kd niarÿxiab niarÿxiab ak sbaib (pN 4 >) b obj kd ãoiab jåtriob (pN : 9.;).

◂

  Chrkhcr 3 eD ak aisbduoiÿj ak ijaiocabr ak F=OrB1 F=OrB1 (obdbr cecriddb)

◂

  Kjrcscr Kjrcscr dc murkt murktcc obj dc aisbduoiÿj aisbduoiÿj ak ChJB? ³ 7.377 7.377 E

◂

  Qitudcr obj dc aisbduoiÿj ak ChJB? ncstc dc cpcrioiÿj ak uj prkoipitcab rblb.

◂

  Cjbtcr kd vbduekj hcstcab hcstcab ak ChJB?.

Aktkreijcoiÿj ak odbrurbs pbr kd Eétbab ak Ebnr Ectkricdks< ◂

  73 Ectrcz Krdkjekykr ak =;7 eD

◂

  73 Murktc ocdimrcac ak =; b ;7 eD.

◂

  73 Ectrcz vbdueétriob ak 377.ed.

◂

  Aisbduoiÿj ak ChJB? kstcjacrizcac.

◂

  @kjbd`tcdkåjc

◂

  _bduoiÿj ak ãoiab jåtriob, NJB? 7.73 E

◂

  _bduoiÿj ak niarÿxiab ak sbaib, JcBN 7.73 E

◂

  _bduoiÿj ijaiocabr ak orbectb ak pbtcsib F=OrB1 F=OrB1 cd ?%. ?%.

◂

  Eukstrc ak chuc jcturcd.

Ektbabdbhåc< ◂

  Ekair 377 eD ak ujc eukstrc ak chuc chuc jcturcd

◂

  Qrcjs`krir c uj ectrcz krdkjekykr ak =;7 eD.

0

 

◂

  Ekair kd pN (8 - 37) uscjab dc `kjbd`tcdkåjc obeb ijaiocabr. ijaiocabr.

◂

  Clustcr kd pN kj ocsb ak skr jkokscrib obj kd niarÿxiab niarÿxiab ak sbaib (pN 4 >) b obj kd ãoiab jåtriob (pN : 9.;).

◂

  Chrkhcr 3 eD ak aisbduoiÿj ak ijaiocabr ak F=OrB1 F=OrB1 (obdbr cecriddb).

◂

  Kjrcscr dc murktc murktc obj dc aisbduoiÿj ak ChJB? kstcjacrizcac.

◂

  Qitudcr dc eukstrc obj dc aisbduoiÿj aisbduoiÿj ak ChJB? ncstc dc cpcrioiÿj ak uj prkoipitcab rblb.

◂

  Cjbtcr kd vbduekj hcstcab hcstcab ak ChJB?

1. ]K_[ ]K_[D DQCAB_ CAB_ E 

3∝

eh /

 

?

7.79189;

3791.711?

;. AI_O AI_O[_ [_IB IBJK JK_ _ Dc kstcjacrizcoiÿj sk rkcdizÿ ekaicjtk dc téojioc dc vcdbrcoiÿj airkotc, utidizcjab obeb ijaiocr cd orbe orbect ctb b ak pbtc pbtcsib sib,, abj abjak ak sk bm bmtu tuvb vb ob obeb eb rksu rksudt dtca cab b 7.79 7.7918 189; 9; E  , u uti tidiz dizcj cjab ab uj ujcc euk eukst strc rc ?

 prbekaic ak 7.37>=h akd JcOd, obj uj hcstb ak prbekaib ak 39.;;eD ak   , cd obepcrcr kstk ?

rksudtcab, obj kd rksudtcab bmtkjiab pbr Mbris P P., ., (=737), quikj utidizcjab obeb ijaiocabr orbectb ak  pbtcsib cd ;% y utidizcjab ujc ecsc 7.=;h y utidizcjab =7 eD ak   ,bmtuvb ujc objokjtrcoiÿj ?

ebdcr ak 7.790?1E 7.790?1E  , kstk rksudtcab rksudtcab ks obepcrcmdk obepcrcmdk obj kd rksudt rksudtcab cab bmtkj bmtkjiab iab aurcjtk aurcjtk dc prãotioc prãotioc ?

yc quk dc vcricoiÿj ks euy pkqukóc y cakeãs dc vcricoiÿj ak dc ebdcriaca ks eãs ekjbs 3 ak dc ebdcriaca ijioicd quk rkpbrtc kd `rcsob, quk `uk ak 7.3E, tcemiéj kd vcdbr bmtkjiab sk kjoukjtrc kj kd rcjhb. dc oucjti`ioc oucjti`iocoiÿj oiÿj ak dbs odbrurbs odbrurbs kj dc eukstrc, sk rkcdizÿ pbr kd eétbab EBN], abjak abjak kd ijaiocabr  ijaiocabr  `uk orbectb ak pbtcsib c uj pN ak 8, abjak kd virclk ak ijaiocabr ks akd obdbr rblb dcariddb, hrcoic c dc `brecoiÿj ak uj obepdklb prkoipitcab ak orbectb ak pdctc. Kj kd dcmbrctbrib sk bmtuvb uj vcdbr  3∝

rkdc rkdcti tivc vcek ekjt jtkk euy euy hr hrcj cjak ak eh eh /, quk quk rks rksud udtÿ tÿ skr skr 37 3791 91.7 .711 11?, ?, kstk kstk rks rksud udtc tcab ab ks rkdc rkdcti tivc vcek ekjt jtkk 3∝

obepcrcmdk obj kd rksudtcab bmtkjiab pbr Hcdic O., (=779), quikj bmtuvb 977 eh

/, utidizcjab uj

vbduekj ak dc eukstrc 377 eD, obj uj hcstb ak jitrctb akd pdctc ?7 eD, kj dc obepcrcoiÿj si kxistk ujc vcrico vcricoiÿj iÿj rkd rkdcti ctivce vcekjt kjtkk hrcjak hrcjak,, sk pukak pukak lusti`ioc lusti`iocrr quk kd pN uscab `uk c > y cak cakeãs eãs kd

8

 

dcmbrctbrib abjak sk rkcdizÿ dbs kxpkriekjtbs `uk cobjaioibjcab, btrb dcab kd vbduekj ak dc eukstrc utidizcab tcemiéj `uk 377% eãs hrcjak.

OBJOD[_IBJK_ ◂

  Dc objokjtrcoiÿj ebdcr prbekaib ak dc aisbduoiÿj aisbduoiÿj kstcjacrizcac ak jitrctb ak pdctc ks 7,791> E.

◂

  Dc objokjtrcoiÿj ak odbrurbs prbekaib kj dc eukstrc ak chuc jcturcd ks 3791.711? eh Od› /D.

  0. ]K@K]K ]K@K]KJOI JOIC_ C_ MIMDIB MIMDIBH]Ã H]Ã@IO @IOC_ C_ ◂

◂

◂ ◂

◂

  Suåeioc Suåeioc hkjkrcd hkjkrcd y tkojbdÿhioc tkojbdÿhioc.. (=737). (=737). Pbduek Pbduektråc tråc ak prkoi prkoipitcoi pitcoiÿj. ÿj. ]koupkrcab ]koupkrcab aksak< nttp