Ntau cov oxides ntawm cov hlau nquag, xws li oxides ntawm potassium, sodium los yog lithium, tuaj yeem cuam tshuam nrog dej. Nyob rau hauv cov ntaub ntawv no, cov tebchaw muaj feem xyuam rau hydroxides muaj nyob rau hauv cov tshuaj tiv thaiv cov khoom. Cov yam ntxwv ntawm cov khoom no, cov yam ntxwv ntawm cov txheej txheem tshuaj nyob rau hauv uas cov hauv paus koom nrog, yog vim muaj cov pab pawg hydroxyl hauv lawv cov molecules. Yog li, nyob rau hauv cov kev cuam tshuam ntawm electrolytic dissociation, cov hauv paus raug faib ua hlau ions thiab anions OH-. Yuav ua li cas cov hauv paus cuam tshuam nrog cov hlau tsis yog hlau oxides, acids thiab ntsev, peb yuav xav txog hauv peb tsab xov xwm.
Nomenclature thiab qauv ntawm cov molecule
Txhawm rau lub npe kom raug, koj yuav tsum ntxiv lo lus hydroxide rau lub npe ntawm cov khoom hlau. Cia peb muab cov piv txwv tshwj xeeb. Lub hauv paus aluminium belongs rau amphoteric hydroxides, cov khoom uas peb yuav xav txog hauv tsab xov xwm. Qhov yuav tsum tau muaj nyob rau hauv lub hauv paus molecules ntawm ib pawg hydroxyl khi rau cov hlau cation los ntawm hom ionic daim ntawv cog lus tuaj yeem txiav txim siab sivIndicators xws li phenolphthalein. Nyob rau hauv ib puag ncig dej, qhov ntau dhau ntawm OH- ions yog txiav txim siab los ntawm kev hloov pauv ntawm cov xim ntawm cov tshuaj ntsuas: tsis muaj xim phenolphthalein ua crimson. Yog tias cov hlau muaj ntau qhov valences, nws tuaj yeem tsim ntau lub hauv paus. Piv txwv li, hlau muaj ob lub hauv paus, nyob rau hauv uas lub valence ntawm cov hlau yog 2 los yog 3. Thawj compound yog characterized los ntawm cov cim qhia ntawm yooj yim hydroxides, qhov thib ob yog amphoteric. Yog li ntawd, cov khoom ntawm cov hydroxides siab dua txawv ntawm cov tebchaw uas cov hlau muaj qis dua ntawm valence.
Lub cev yam ntxwv
Cov hauv paus yog cov khoom uas tiv taus cua sov. Nyob rau hauv kev sib cuag nrog dej, lawv muab faib ua soluble (alkali) thiab insoluble. Thawj pab pawg yog tsim los ntawm chemically active hlau - cov ntsiab lus ntawm thawj thiab thib ob pawg. Cov dej-insoluble tshuaj yog tsim los ntawm atoms ntawm lwm yam hlau, uas nws cov hauj lwm yog inferior rau sodium, potassium los yog calcium. Piv txwv ntawm cov tebchaw no yog cov hlau lossis tooj liab. Cov yam ntxwv ntawm hydroxides yuav nyob ntawm seb cov tshuaj twg lawv koom nrog. Yog li, alkalis yog thermally ruaj khov thiab tsis decompose thaum rhuab, thaum dej-insoluble bases raug puas tsuaj nyob rau hauv qhov kev txiav txim ntawm kub kub, tsim ib tug oxide thiab dej. Piv txwv li, lub hauv paus tooj liab decomposes raws li hauv qab no:
Cu(OH)2=CuO + H2O
tshuaj lom neeg ntawm hydroxides
Kev sib cuam tshuam ntawm ob pawg tseem ceeb tshaj plaws ntawm kev sib txuas -acids thiab bases hu ua neutralization cov tshuaj tiv thaiv hauv chemistry. Lub npe no tuaj yeem piav qhia los ntawm qhov tseeb tias cov tshuaj lom neeg hydroxides thiab acids tsim cov khoom nruab nrab - ntsev thiab dej. Raws li, qhov tseeb, kev sib pauv ntawm ob yam khoom nyuaj, neutralization yog yam ntxwv ntawm ob qho tib si alkalis thiab dej-insoluble bases. Ntawm no yog qhov sib npaug rau cov tshuaj tiv thaiv nruab nrab ntawm caustic potash thiab hydrochloric acid:
KOH + HCl=KCl + H2O
Ib yam khoom tseem ceeb ntawm alkali hlau hauv paus yog lawv lub peev xwm los teb cov kua qaub oxides, ua rau ntsev thiab dej. Piv txwv li, dhau los ntawm cov pa roj carbon dioxide los ntawm sodium hydroxide, koj tuaj yeem tau txais nws cov carbonate thiab dej:
2NaOH + CO2=Na2CO3 + H 2O
Ion pauv cov tshuaj tiv thaiv suav nrog kev cuam tshuam ntawm alkalis thiab ntsev, uas ua rau tsim cov hydroxides tsis txaus lossis ntsev. Yog li, ntxiv dropwise ib qho kev daws ntawm caustic soda rau kev daws ntawm tooj liab sulfate, koj tuaj yeem tau txais xiav jelly zoo li precipitate. Nws yog tooj liab puag, insoluble hauv dej:
CuSO4 + 2NaOH=Cu(OH)2 + Na2 SO 4
Cov khoom siv tshuaj ntawm hydroxides, insoluble hauv dej, sib txawv ntawm alkalis vim tias lawv poob dej thaum cua sov me ntsis - lawv dehydrate, tig mus rau hauv daim ntawv ntawm cov oxide yooj yim sib xws.
Thaj chaw nthuav tawm cov khoom dual
Yog hais tias ib yam khoom los yog ib qho complex tshuaj tuaj yeem hnov mob nrog ob qho tib si acids thiab alkalis, nws yog hu ua amphoteric. Cov no suav nrog, piv txwv li, zinc,aluminium thiab lawv cov hauv paus. Cov khoom ntawm amphoteric hydroxides ua rau nws muaj peev xwm sau lawv cov qauv molecular ob qho tib si hauv daim ntawv ntawm cov hauv paus, thaum cais pawg hydroxo, thiab hauv daim ntawv ntawm cov kua qaub. Cia peb nthuav qhia ob peb qhov sib npaug rau cov kev cuam tshuam ntawm aluminium puag nrog hydrochloric acid thiab sodium hydroxide. Lawv qhia txog cov khoom tshwj xeeb ntawm amphoteric hydroxides. Qhov thib ob qhov tshwm sim tshwm sim nrog kev lwj ntawm alkali:
2Al(OH)3 + 6HCL=2AlCl3 + 3H2O
Al(OH)3 + NaOH=NaAlO2 + 2H2O
Cov khoom ntawm cov txheej txheem yuav yog dej thiab ntsev: txhuas chloride thiab sodium aluminate. Txhua lub hauv paus amphoteric yog insoluble hauv dej. Lawv raug mined los ntawm kev sib cuam tshuam ntawm cov ntsev thiab alkalis.
Txoj kev tau txais thiab thov
Hauv kev lag luam uas xav tau ntau cov alkalis, lawv tau txais los ntawm electrolysis ntawm cov ntsev uas muaj cations ntawm cov hlau nquag ntawm thawj thiab thib ob pawg ntawm lub sijhawm. Cov khoom siv raw rau kev rho tawm, piv txwv li, caustic sodium, yog cov tshuaj ntsev ntau. Qhov sib npaug ntawm cov tshuaj tiv thaiv yuav yog:
2NaCl + 2H2O=2NaOH + H2 + Cl2
Lub hauv paus ntawm cov hlau tsis muaj zog hauv chav kuaj tau txais los ntawm kev cuam tshuam ntawm alkalis nrog lawv cov ntsev. Cov tshuaj tiv thaiv belongs rau hom kev sib pauv ion thiab xaus nrog nag lossis daus ntawm lub hauv paus. Ib txoj hauv kev yooj yim kom tau txais alkalis yog kev hloov pauv ntawm cov hlau nquag thiab dej. Nws yog nrog los ntawm cua sov ntawm cov reacting sib tov thiab yog hom exothermic.
Cov khoom ntawm hydroxides yog siv hauv kev lag luam. Alkalis ua lub luag haujlwm tshwj xeeb ntawm no. Lawv yog siv los ua purifiers rau kerosene thiab roj av, ua xab npum, ua cov tawv nqaij, thiab nyob rau hauv technologies rau zus tau tej cov rayon thiab ntawv.
