Qhov sib txawv tseem ceeb ntawm methyl txiv kab ntxwv thiab phenolphthalein yog cov xim ntawm methyl txiv kab ntxwv hloov los ntawm liab mus rau daj thaum hloov los ntawm acidic mus rau nruab nrab nruab nrab, whereas xim ntawm phenolphthalein hloov los ntawm colorless mus rau liab thaum hloov los ntawm acidic mus rau nruab nrab nruab nrab..
Ib qho taw qhia yog ib qho khoom siv hauv kev tshuaj ntsuam titrimetric txhawm rau nrhiav qhov kawg qhov twg cov tshuaj tiv thaiv xaus. Peb tuaj yeem txiav txim siab tus nqi ntsuas siv los nrhiav ntau yam tshuaj sib txawv raws li.
Methyl txiv kab ntxwv yog dab tsi?
Methyl txiv kab ntxwv yog pH qhov taw qhia uas qhia cov xim liab thiab xim daj ntawm cov pH sib txawv. Nws yog siv ntau zaus hauv cov tswv yim titration vim nws txawv thiab meej xim txawv. Nws qhia cov xim liab hauv acidic nruab nrab thiab xim daj hauv nruab nrab nruab nrab. Cov xim hloov ntawm pKa, yog li nws feem ntau yog siv rau hauv titration rau acids. Txawm hais tias nws tsis muaj tag nrho cov spectrum ntawm cov xim hloov, nws muaj ib tug ntse kawg point. Thaum cov tshuaj ua acidic tsawg, methyl txiv kab ntxwv hloov xim ntawm liab mus rau txiv kab ntxwv. Thaum kawg, nws tig daj, muab qhov kawg ntawm titration.
Cov tshuaj formula ntawm methyl txiv kab ntxwv yog C14H14N3NaO 3S. Nws muaj molar loj ntawm 327.33 g / mol. Nws cov tsos tuaj yeem piav qhia tias yog txiv kab ntxwv lossis daj. Qhov ceev ntawm methyl txiv kab ntxwv yog 1.258 g / cm3Nws melting point yog >300 degrees Celsius, thiab nws decomposes ntawm kub dua. Nws yog dej-soluble tsis zoo. Hauv diethyl ether, methyl txiv kab ntxwv yog insoluble. Lub pKa ntawm qhov ntsuas no yog 3.47 nyob rau hauv dej ntawm ib txwm chav tsev kub (25 degrees Celsius).
Ntxiv mus, peb tuaj yeem muab lwm qhov ntsuas siv methyl txiv kab ntxwv, thiab nws yog hu ua xylene cyanol. Nws hloov los ntawm grey-violet mus rau ntsuab raws li kev daws yuav yooj yim dua. Nws yog lub npe hu ua ib qho kev hloov kho qhov taw qhia. Txawm li cas los xij, methyl txiv kab ntxwv muaj mutagenic zog. Yog li ntawd, nws raug suav hais tias yog tshuaj lom uas yuav tsum tau saib xyuas.
Phenolphthalein yog dab tsi?
Phenolphthalein yog pH qhov taw qhia uas muaj txiaj ntsig zoo li cov kua qaub-base titration indicator. Nws yog ib qho kev qhia uas feem ntau siv hauv cov txheej txheem titration. Cov tshuaj formula ntawm phenolphthalein yog C20H14O4. Lub npe no yog hu ua "Hin" los yog "phph." Cov xim acidic ntawm phenolphthalein yog xim tsis muaj xim, thaum lub ntsiab xim ntawm qhov taw qhia yog liab dawb. Yog li ntawd, thaum mus los ntawm acidic mus rau nruab nrab nruab nrab, cov xim hloov los ntawm tsis muaj xim mus rau liab. Qhov pH ntau rau qhov kev hloov xim no yog nyob ib ncig ntawm 8.3 - 10.0 pH.
Ntxiv mus, qhov ntsuas phenolphthalein yog me ntsis dej-soluble, thiab nws feem ntau yaj hauv cawv. Qhov no yog vim li cas peb tuaj yeem yooj yim siv lawv hauv titrations. Phenolphthalein yog ib qho tsis muaj zog acid uas tuaj yeem tso cov protons rau hauv cov tshuaj. Lub acidic daim ntawv ntawm phenolphthalein yog nonionic thiab tsis muaj xim. Daim ntawv deprotonated ntawm phenolphthalein yog xim liab thiab yog ib daim ntawv ionic. Yog hais tias peb ntxiv ib lub hauv paus rau cov tshuaj tiv thaiv sib tov uas muaj ib tug phenolphthalein qhia, qhov sib npaug ntawm cov ionic thiab nonionic cov ntaub ntawv nyhav hloov mus rau lub xeev deprotonated vim hais tias cov protons raug tshem tawm los ntawm cov tshuaj.
Thaum xav txog kev sib xyaw ntawm phenolphthalein qhia, peb tuaj yeem tsim nws los ntawm kev sib xyaw ntawm phthalic anhydride nyob rau hauv muaj ob qhov sib npaug ntawm phenol nyob rau hauv acidic tej yam kev mob. Ntxiv mus, cov tshuaj tiv thaiv no tuaj yeem ua rau muaj kev sib xyaw ntawm zinc chloride thiab thionyl chloride.
Qhov txawv ntawm Methyl Txiv kab ntxwv thiab Phenolphthalein yog dab tsi?
Qhov sib txawv tseem ceeb ntawm methyl txiv kab ntxwv thiab phenolphthalein yog cov xim ntawm methyl txiv kab ntxwv hloov ntawm liab mus rau daj thaum hloov los ntawm acidic mus rau nruab nrab nruab nrab, whereas xim ntawm phenolphthalein hloov los ntawm tsis muaj xim mus rau liab thaum hloov los ntawm acidic mus rau nruab nrab nruab nrab.. Hauv methyl txiv kab ntxwv, pH ntau rau qhov kev hloov xim no yog nyob ib puag ncig 3.1 - 4.4, whereas, hauv phenolphthalein, pH ntau rau qhov hloov xim yog nyob ib ncig ntawm 8.3 - 10.0 pH.
Cov hauv qab no qhia txog qhov sib txawv ntawm methyl txiv kab ntxwv thiab phenolphthalein hauv daim ntawv qhia rau kev sib piv ntawm ib sab.
Summary – Methyl Orange vs Phenolphthalein
Methyl txiv kab ntxwv thiab phenolphthalein yog cov ntsuas pH uas muaj txiaj ntsig zoo li ntsuas titration. Qhov sib txawv tseem ceeb ntawm methyl txiv kab ntxwv thiab phenolphthalein yog cov xim ntawm methyl txiv kab ntxwv hloov ntawm liab mus rau daj thaum hloov los ntawm acidic mus rau hauv nruab nrab nruab nrab, whereas xim ntawm phenolphthalein hloov los ntawm colorless mus rau liab dawb thaum hloov los ntawm acidic mus rau nruab nrab nruab nrab.
