Chemistry yog ib qho kev tshawb fawb uas kawm txog ntau yam kev tshwm sim tshwm sim hauv cov xwm txheej, nrog rau kev sib cuam tshuam ntawm qee qhov sib txuas nrog lwm tus. Cov khoom tseem ceeb ntawm no yog cov kua qaub thiab alkalis, cov tshuaj tiv thaiv uas feem ntau hu ua neutralization. Lawv ua rau cov dej-soluble ntsev.
yog dab tsi lye
Hydroxides ntawm alkaline (hlau ntawm thawj pab pawg ntawm lub ntsiab (A) subgroup nyob rau hauv lub sij hawm lub sij hawm ntawm tshuaj cov ntsiab lus ntawm D. I. Mendeleev) thiab alkaline ntiaj teb (hlau ntawm lub thib ob pab pawg neeg ntawm lub ntsiab (A) subgroup, suav nrog. calcium) cov hlau uas cuam tshuam nrog dej thiab yaj tag nrho hauv nws, hu ua alkalis. Txij li thaum lawv muaj peev xwm rhuav tshem cov khoom siv organic (tawv, ntoo, ntawv), lawv hu ua caustic. Piv txwv li, potassium hydroxide (KOH) yog caustic potash, barium (Ba(OH)2) yog caustic barium, thiab lwm yam.
Lub cev muaj zog ntawm lub hauv paus muaj zog
Raws li lub ntsiab lus ntawm qhov alkali yog dab tsi, peb tuaj yeem ntxiv tias cov hydroxides no kuj yog cov khoom hygroscopic (muaj peev xwm nqus cov pa los ntawm huab cua.dej) cov khoom dawb. Cov alkalis uas muaj zog tshaj plaws yog cesium hydroxides CsOH thiab radium Ra(OH)2. Cov tshuaj tiv thaiv Alkali feem ntau yog nrog los ntawm kev tso cua sov (exothermic). Tsis tas li ntawd, lub cev lub cev ntawm cov hauv paus no suav nrog lawv lub peev xwm los yaj hauv qee cov organic tebchaw, piv txwv li, hauv cawv: methanol thiab ethanol.
tshuaj muaj zog
Txoj kev daws teeb meem ntawm alkalis muaj peev xwm nkag mus rau hauv ntau yam tshuaj tiv thaiv.
Lub hauv paus muaj zog muaj peev xwm cuam tshuam nrog acidic thiab amphoteric oxides:
- KOH + SO3=K2SO4 + H2O (SO3 is an acidic oxide);
- 2KOH + Al2O3=2KAlO2 + H2O (cov tshuaj tiv thaiv fusion, tshwm sim thaum cua sov, qhov twg Al2O3 yog amphoteric oxide);
- 2KOH + Al2O3 + 3H2O=2K[Al(OH)4] (cov tshuaj tiv thaiv pib nrog kev tsim cov ntsev ntsev - poov tshuaj tetrahydroxoaluminate).
Thaum hnov mob nrog amphoteric hlau (Zn, Al thiab lwm yam), kev tsim ntawm ob qho tib si yaj thiab cov ntsev sib xyaw ua ke kuj ua tau. Ntxiv mus, ob qho kev cuam tshuam nrog kev hloov pauv ntawm gaseous hydrogen:
- 2KOH + 2Al=2KAlO2 + H2;
- 2KOH + 2Al + 6H2O=2K[Al(OH)4] + 3H2.
Alkalis kuj tuaj yeem ua rau cov ntsev, ua rau muaj lwm lub hauv paus thiab lwm cov ntsev. Cov xwm txheej rau cov tshuaj tiv thaiv mus ntxiv yog qhov tshwm sim, ib qho ntawm cov khoom tsim yuav tsum yog insoluble hauv dej:
NaOH + CuSO4=Na2SO4 + Cu(OH)2.
Raws li tau hais ua ntej, alkalis thiab acids nkag mus rau hauvneutralization cov tshuaj tiv thaiv, ntsev thiab dej yog tsim:
NaOH + HCl=NaCl + H2O.
Alkalis hnov qab nrog lwm lub hauv paus tsuas yog tias lawv yog hydroxides ntawm amphoteric hlau:
NaOH + Al(OH)3=Na[Al(OH)4].
Qee ntawm lawv tuaj yeem cuam tshuam nrog ntau cov organic: esters, amides, polyhydric alcohols:
2C2H6O2 + 2NaOH=C2H4O2Na2 + 2H2O (cov tshuaj tiv thaiv yog sodium alkoxide).
Yuav ua li cas thiaj muaj zog hauv qab
Alkalis tau txais ntau txoj hauv kev hauv kev lag luam thiab hauv chav kuaj.
Hauv kev lag luam kev lag luam, muaj ntau txoj hauv kev tsim cov alkalis: pyrolysis, txiv qaub, ferrite, electrolysis, uas tau muab faib ua diaphragm, membrane thiab mercury txoj kev ntawm cov kua thiab cov khoom cathodes.
Qhov no yog electrolysis ntawm kev daws teeb meem ntawm sodium thiab potassium chlorides, tom qab uas cov tshuaj chlorine thiab hydrogen raug tso tawm ntawm anode thiab cathode, thiab cov hydroxides tau txais:
- 2NaCl + 2H2O=H2 + Cl2 + 2NaOH;
- 2KCl + 2H2O=H2 + Cl2 + 2KOH.
Thaum pyrolysis ntawm 1000 degrees, qhov tsim ntawm sodium oxide tshwm sim thawj theem:
Na2CO3=Na2O + CO2.
Nyob rau theem thib ob, qhov tshwm sim txias oxide yog yaj hauv dej, vim tias qhov tsim nyog alkali tau txais:
Na2O + H2O=2NaOH.
Chaw kuaj mob kuj tseem siv electrolysis. Alkalis tseem tuaj yeem tau txais los ntawm kev nthuav tawm cov hlau sib xws rau hauv dej lossis los ntawm kev ua kom cov ntsev ntawm cov hlau no nrog rau lwm cov hauv paus, vim li ntawdQhov tsim nyog alkali yog tau thiab cov khoom thib ob ntawm cov tshuaj tiv thaiv, insoluble hauv dej, yog ntsev.
Thaum cesium thiab dej sib cuam tshuam, cesium hydroxide tau txais thiab hydrogen tawm (cov tshuaj tiv thaiv tshwm sim txawm tias kub ntawm -120 degrees):
2Cs + 2H2O=2CsOH + H2.
Raws li qhov tshwm sim ntawm cov dej ntawm lithium oxide, alkali tau txais:
Li2O + 2H2O=2LiOH + H2.
Daim ntawv thov
Raws li lub ntsiab lus ntawm alkali yog dab tsi, ib tus tuaj yeem nkag siab tias lawv tau siv dav tsis yog hauv kev lag luam xwb, tab sis kuj tseem nyob hauv lub neej txhua hnub:
- Kev tua kab mob hauv pas dej rau nuv ntses.
- Ua chiv.
- In tshuaj.
- In paper production.
- Kev tsim cov roj hmab hluavtaws.
- Tau tau xab npum thiab xab npum.
- Electrolyte Cheebtsam hauv alkaline roj teeb.
- Carbon dioxide absorber (lithium hydroxide).
- Kev tsim cov roj nplua nyeem.
- Dyes hauv kev tsim khoom noj (khoom noj khoom haus ntxiv).
- roj teeb electrolytes (potassium hydroxide).
- Tshuaj cov kav dej thiab cov dab dej los ntawm cov khoom noj.
- Acid neutralization.
- Catalysts hauv tshuaj lom neeg kev lag luam.
- Tshuaj ua cov duab.
Kev Tiv Thaiv
Nws dhau los ua pom tseeb tias alkalis xws li hydroxides ntawm sodium, lithium, potassium, cesium thiab lwm yam tuaj yeem ua rau mob hnyav thiab kub hnyiab ntawm daim tawv nqaij thiab mucous daim nyias nyias ntawm lub qhov muag, txawm tias qhov me me ntawm cov khoom sib xyaw tuaj yeem muaj. Tiv thaiv qhov noNws yog ib qho tsim nyog yuav tsum hnav tsom iav, hnab looj tes roj hmab, thiab tag nrho cov khoom siv kho mob tshwj xeeb uas tsis tso cai rau cov khoom cuam tshuam nrog alkalis.
