Amphoteric oxides. Nine waiwai, he kaʻina hana no ka hoomakaukau ana i

Amphoteric oxides (ka pālua waiwai) - i loko o ka hapanui hihia metala oxides a i haʻahaʻa electronegativity. Ke kaumaha ma muli mawaho olelo ho'āʻo kekahiʻakika'okesaside a waiwai. Mau oxides i hoohuiia e hoʻololi i eliiaʻi, a nō kāu ho'āʻo i ka kēia'okesaside Huiia: LL, lll, lV.

Ano he kumu hoʻohālike o ka amphoteric oxides: kiniki'okesaside (ZnO), chromium'okesaside lll (Cr2O3), Aluminum'okesaside (Al2O3),'okesaside LL ke tina (SnO), ke tina'okesaside lV (SnO2), alakai'okesaside LL (PbO), alakai'okesaside lV (PbO2) , titanium'okesaside lV (TiO2), manganese'okesaside lV (MnO2), hao'okesaside lll (Fe2O3), beryllium'okesaside (BeO).

Nā reactions typical o amphoteric oxides:

1. mau oxides i pane koke me nāʻakika ikaika. Ma keia palapala i ka paʻakai o kēia mau ia nāʻakika. Reactions o kēia 'ano mea o ka hoike ana o na waiwai o ke kumu o type. No kekahi laʻana: ZnO (kiniki'okesaside) + H2SO4 (hydrochloricʻakika) → ZnSO4 (kiniki sulufahate) + H2O (ka wai).

2. Ma ka naoh me ka ikaika alkalis amphoteric oxides, hydroxides ho'āʻo ʻakika waiwai. Ma keia duality o ka waiwai (a laila, amphoteric) ua hoikea mai oia, i loko o ke kahua o nā paʻakai.

Ma ka mahele heheʻe i ka ma naoh me ka mekala 'åkilikai ka paʻakai ua hana i ka awelika maʻamau, no kekahi laʻana:
ZnO (kiniki'okesaside) + 2NaOH (paʻakai hydroxide) → Na2ZnO2 (maʻamau kaulana paʻakai) + H2O (ka wai).
Al2O3 (alumina) + 2NaOH (paʻakai hydroxide) = 2NaAlO2 + H2O (ka wai).
2Al (OH) 3 (Aluminum hydroxide) + 3SO3 (ka sulfur'okesaside) = Al2 (SO4) 3 (Aluminum sulufahate) + 3H2O (ka wai).

Ka pāʻoihana amphoteric oxides ma naoh me ka mekala 'åkilikai, e hana i ka luna' paakai, no kekahi laʻana: Al2O3 (alumina) + 2NaOH (paʻakai hydroxide) + 3H2O (ka wai) + 2Na (Al (OH) 4) (i ka luna 'paakai o ka paʻakai tetragidroksoalyuminat).

3. kēlā me kekahi amphoteric metala'okesaside mai he ōhumu helu. No ka laʻana i kiniki (Zn) - 4, Aluminum (Al) - 4 a 6, no ka chromium (Cr) - 4 (pohihihi) a me 6.

4. Amphoteric'okesaside 'Aʻole i pane koke me ka wai, a aole hoi e hoike mai i loko.

He aha reactions hoao amphoteric metala?

KŘpa a olelo ana, he amphoteric hehee ai e ho'āʻo i ka waiwai o nā mea hiki ke hooheheeia, a nonmetals. Oia ano hiʻona mea i loaʻa i loko o nā kumu o A pūʻulu: E (beryllium), HI (gallium), GE (germanium), Sn (piuta), PB, Sb (antimony),ʻelua (bismuth), a me kekahi mea e ae, e like me na mea he nui o na kumu mua B -groups - he Cr (chromium), HI (manganese), Fe (hao), Zn (kiniki), Cd (cadmium), a me kekahi poe e ae.

Mākou e hoao hoi i ka kēia Nine Inch reactions amphoteric Nine Inch hehee ai kiniki (Zn):

1. Zn (OH) 2 (kiniki hydroxide) + N2O5 (dinitrogen pentoxide) = Zn (NO3) 2 (kiniki nitrate) + H2O (ka wai).
ZnO (kiniki'okesaside) + 2HNO3 (nitricʻakika) = Zn (NO3) 2 (kiniki nitrate) + H2O (ka wai).

b) Zn (OH) 2 (kiniki hydroxide) + Na2O (paʻakai'okesaside) = Na2ZnO2 (paʻakai dioksotsinkat) + H2O (ka wai).
ZnO (kiniki'okesaside) + 2NaOH (paʻakai hydroxide) = Na2ZnO2 (paʻakai dioksotsinkat) + H2O (ka wai).

Ma ia hihia, ina ka hehee ai me ka pālua waiwai o ka hui i ka kēia'okesaside, kona pālua (amphoteric) waiwai loa noticeably ana i loko o ka palapala'okesaside anu u.

Like laʻana hiki ke chrome (Cr). Kēia hehee ai i ke kēia'okesaside Huiia: 3+, 2+ 6+. Ma ka hihia o ekolu walaʻauʻana a me kaʻakika ka waiwai i olelo ia o ka hola like, oiai y me Cr +2 walaʻauʻana waiwai lanakila, a ma Cr +6 -ʻakika. Eia nā reactions i hooiaio keia olelo:

Cr + 2 → CrO (chromium'okesaside +2), Cr (OH) 2 → CrSO4;
Cr + 3 → Cr2O3 (chromium'okesaside +3), Cr (OH) 3 (chromium hydroxide) → KCrO2 ole chromium sulphate Cr2 (SO4) 3;
Cr + 6 → CrO3 (chromium'okesaside +6), H2CrO4 → K2CrO4.

Ma ka hapanui o na hihia amphoteric oxides o Nine Inch nā kumumea i loko o'okesaside moku'āina +3 nei i loko o ka meta palapala. Like laʻana hiki ke kākau i nā: Aluminum hydroxide'okesaside (Nine Inch haʻilula Alo (OH) a me ka hao metahydroxide (Nine Inch FeO (OH) haʻilula) ...

Pehea e amphoteric oxides?

1. Ka loa pono papa hana no lākou hoomalolo mea kimu, mai ka koʻana koko pāʻoihana hoʻohana'amoniuma hydroxide, i mea he nawaliwali kumu. No kekahi laʻana:
Al (NO3) 3 (Aluminum nitrate) + 3 (H2OxNH3) (koʻana koko pāʻoihana o ka ammonia hydrate) = Al (OH) 3 (amphoteric'okesaside) + 3NH4NO3 (naoh ua hana ma lalo o ka wela iwakalua degere).
Al (NO3) 3 (Aluminum nitrate) + 3 (H2OxNH3) (koʻana koko'amoniuma hydroxide) = Alo (OH) (amphoteric'okesaside) + 3NH4NO3 + H2O (naoh hana ma 80 ° C)

Ma ka wehe aʻe naoh o kēia 'ano i loko o ka hihia o ka oi mekala' åkilikai Aluminum hydroxide e ole precipitate. O ke kumu ho i ka mea i ka Aluminum hele i loko o ka anion no o kona pālua waiwai: Al (OH) 3 (Aluminum hydroxide) + OH- (oi mekala 'åkilikai) = [Al (OH) 4] - (Aluminum hydroxide anion).

Ano he kumu hoʻohālike o ia 'ano o ka naoh:
Al (NO3) 3 (Aluminum nitrate) + 4NaOH (oi paʻakai hydroxide) = 3NaNO3 + Na (Al (OH) 4).
ZnSO4 (kiniki sulufahate) + 4NaOH (oi paʻakai hydroxide) = Na2SO4 + Na2 (Zn (OH) 4).

Paʻakai i i hana i ka mea ia manawa, i luna 'i huiʻia. Ka mea, nā luna 'anions: (Al (OH) 4) - a me kekahi (Zn (OH) 4) 2-. No laila au i kapa aku i ka paʻakai: Na (Al (OH) 4) - paʻakai tetragidroksoalyuminat, Na2 (Zn (OH) 4) - paʻakai tetragidroksotsinkat. Naoh huahana o ka Aluminum a kiniki oxides me ka puaʻa hiwa paʻa mekala 'åkilikai i kapa okoa: NaAlO2 - paʻakai dioksoalyuminat a me Na2ZnO2 - paʻakai dioksotsinkat.