Muaj hydroxides uas ua rau cov kua qaub thiab cov hauv paus, nyob ntawm cov xwm txheej. Cov tebchaw uas nthuav tawm ob qhov xwm txheej yog hu ua amphoteric hydroxides. Lawv tsim los ntawm cov hlau cation thiab hydroxide ion, zoo li txhua lub hauv paus. Tsuas yog cov hydroxides uas muaj cov hlau hauv qab no hauv lawv cov muaj pes tsawg leeg muaj peev xwm ua raws li cov kua qaub thiab cov hauv paus: Be, Zn, Al, Pb, Sn, Ga, Cd, Fe, Cr (III), thiab lwm yam. Periodic system ntawm D. THIAB. Mendeleev, hydroxides nrog ob qhov xwm txheej hlau uas ze tshaj plaws rau cov hlau tsis muaj hlau. Nws ntseeg tau tias cov ntsiab lus no yog cov ntawv hloov pauv, thiab kev faib ua cov hlau thiab cov hlau tsis yog hlau yog qhov tsis txaus ntseeg.
Amphoteric hydroxides yog cov khoom hmoov zoo crystalline, uas feem ntau muaj xim dawb, tsis yaj hauv dej thiab ua tsis zoo tam sim no (tsis muaj zog electrolytes). Txawm li cas los xij, qee qhov ntawm cov hauv paus no tuaj yeem yaj hauv cov kua qaub thiab alkalis. Lub dissociation ntawm "dual compounds" nyob rau hauv aqueous daws tshwm sim raws li hom acids thiabthaj av. Qhov no yog vim lub fact tias lub zog tuav ntawm hlau thiab oxygen atoms (Me-O) thiab ntawm oxygen thiab hydrogen atoms (O-H) yog xyaum sib npaug, piv txwv li. Kuv - O - N. Yog li ntawd, cov ntawv cog lus no yuav tawg ib txhij, thiab cov tshuaj no yuav sib cais ua H + cations thiab OH- anions.
Lub amphoteric hydroxide - Be(OH)2 yuav pab kom paub meej txog qhov xwm txheej ntawm cov tebchaw no. Xav txog kev sib cuam tshuam ntawm beryllium hydroxide nrog cov kua qaub thiab lub hauv paus.
1. Be(OH)2+ 2HCl –BeCl2+2H2O.
2. Be(OH)2 + 2KOH – K2 [Be(OH)4] – potassium tetrahydroxoberyllate.
Nyob rau hauv thawj rooj plaub, cov tshuaj tiv thaiv neutralization tshwm sim, qhov tshwm sim ntawm uas yog tsim ntsev thiab dej. Hauv qhov thib ob, cov khoom siv tshuaj tiv thaiv yuav yog ib qho kev sib xyaw ua ke. Cov tshuaj tiv thaiv neutralization yog ib qho tseem ceeb rau tag nrho cov hydroxides yam tsis muaj kev zam, tab sis kev sib cuam tshuam nrog lawv tus kheej zoo yog ib txwm rau amphoteric sawv daws yuav. Lwm cov tshuaj amphoteric kuj tseem tuaj yeem pom cov khoom zoo li no - oxides thiab cov hlau lawv tus kheej, uas lawv tsim.
Lwm cov khoom siv tshuaj ntawm cov hydroxides yuav yog tus yam ntxwv ntawm txhua lub hauv paus:
1. Thermal decomposition, cov khoom siv tshuaj tiv thaiv - cov khoom siv oxide thiab dej:
2. Neutralization cov tshuaj tiv thaiv nrog acids.
3. Cov tshuaj tiv thaiv acid oxides.
Koj kuj yuav tsum nco ntsoov tias muaj cov tshuaj uas amphoteric hydroxides tsis uakev sib tham, i.e. tsis muaj tshuaj tiv thaiv, qhov no yog:
- non-metals;
- metals;
- insoluble bases;
- amphoteric hydroxides.
- midium ntsev.
Cov tebchaw no tau los ntawm alkali nag lossis daus ntawm cov ntsev tov:
BeCl2 + 2KOH – Be(OH)2+ 2KCl.
Ntshav ntawm qee cov ntsiab lus hauv chav kawm ntawm cov tshuaj tiv thaiv no tsim hydrate, cov khoom uas yuav luag tag nrho cov hydroxides nrog ob qhov xwm txheej. Cov hauv paus zoo ib yam nrog ob lub zog yog ib feem ntawm cov zaub mov, nyob rau hauv daim ntawv uas lawv muaj nyob rau hauv cov xwm (bauxite, goethite, thiab lwm yam).
Yog li, amphoteric hydroxides yog cov tshuaj inorganic, uas, nyob ntawm qhov xwm txheej ntawm cov tshuaj uas cuam tshuam nrog lawv, tuaj yeem ua raws li cov hauv paus lossis cov kua qaub. Feem ntau, lawv sib raug rau amphoteric oxides uas muaj cov hlau sib xws (ZnO-Zn(OH)2; BeO - Be(OH)2), etc. e.).
