Amphoteric oxides. Chemical feartan, pròiseas airson a bhith ag ullachadh

Amphoteric oxides (a 'toirt dà feartan) - sa chuid as motha de chùisean meatailt oxides a tha ìosal electronegativity. A rèir thaisbeanadh air taobh a-muigh na h-ogsaid sam bith searbh no feartan. Oxides iad sin air an cruthachadh le meatailtean eadar-ghluasad, a tha a 'taisbeanadh mar as trice a leanas oxidation stàitean: ll, lll, Lv.

Eisimpleirean de amphoteric oxides: sinc ogsaid (ZnO), Chromium ogsaid lll (Cr2O3), almain ogsaid (Al2O3), ogsaid ll tin (SnO), an staoin ogsaid Lv (SnO2), luaidhe ogsaid ll (PbO), luaidhe ogsaid Lv (PbO2) , TITANIUM ogsaid Lv (TiO2), mangaineis ogsaid Lv (MnO2), iarann ogsaid lll (Fe2O3), beryllium ogsaid (Beò).

Tha ath-bhualaidhean àbhaisteach de amphoteric oxides:

1. Tha iad sin a 'gabhail oxides dòcha le làidir ri tachartasan shearbhagan. Anns an fhoirm seo tha an salann de na h-aon ri tachartasan shearbhagan. Iom-seòrsa seo tha foillseachadh na feartan bunaiteach seòrsa. Mar eisimpleir: ZnO (sinc ogsaid) + H2SO4 (hydrochloric acid) → ZnSO4 (sinc sulfate) + H2O (uisge).

2. Ann an reaction le làidir alkalis amphoteric oxides, hydroxides thaisbeanadh searbh lotaichean. Anns an Duality de thogalaichean (i.e., amphoteric) a dh'fhoillsich ann an cruthachadh dà salann.

Anns a 'leaghadh le reaction leis an alkali salainn a chruthachadh cuibheasach àbhaisteach, mar eisimpleir:
ZnO (sinc ogsaid) + 2NaOH (Sòidiam hydroxide) → Na2ZnO2 (cuibheas àbhaisteach salainn) + H2O (uisge).
Al2O3 (alumina) + 2NaOH (Sòidiam hydroxide) = 2NaAlO2 + H2O (uisge).
2Al (OH) 3 (aluminium hydroxide) + 3SO3 (pronnasg ogsaid) = Al2 (SO4) 3 (aluminium sulfate) + 3H2O (uisge).

Tha fuasgladh amphoteric oxides le reaction le alkali a chruthachadh iom-fhillte salainn, mar eisimpleir: Al2O3 (alumina) + 2NaOH (Sòidiam hydroxide) + 3H2O (uisge) + 2Na (Al (OH) 4) (a-fhillte salainn sodium tetragidroksoalyuminat).

3. Tha gach sam bith amphoteric meatailt ogsaid a tha co-òrdanachadh àireamh. Mar eisimpleir gu sinc (Zn) - 4, almain (Al) - 4 no 6, airson Chromium (CR) - 4 (ainneamh) no 6.

4. Amphoteric ogsaid Chan eil a 'gabhail ri uisge agus chan eil sgaoileadh ann.

Dè iom- dearbhadh amphoteric meatailt?

An ìre mhath a 'bruidhinn, an amphoteric eileamaid Faodaidh feartan dà chuid meatailtean agus nonmetals. A leithid feart feart a tha an làthair ann an eileamaidean de A buidhnean: Bi (beryllium), Ga (gallium), Ge (germanium), Sn (tin), PB, SB (antimony), Bi (bismuth), agus cuid eile, cho math ri mòran de na h-eileamaidean B -groups - a Kr (Chromium), MN (mangaineis), Fe (iarann), Zn (sinc), Cd (cadmium), agus feadhainn eile.

Tha sinn a-nis a 'dearbhadh na leanas ceimigeach amphoteric eileamaid cheimigeach a sinc (Zn):

1. Zn (OH) 2 (sinc hydroxide) + N2O5 (dinitrogen pentoxide) = Zn (NO3) 2 (sinc nitrate) + H2O (uisge).
ZnO (sinc ogsaid) + 2HNO3 (nitric acid) = Zn (NO3) 2 (sinc nitrate) + H2O (uisge).

b) Zn (OH) 2 (sinc hydroxide) + Na2O (sodium ogsaid) = Na2ZnO2 (sodium dioksotsinkat) + H2O (uisge).
ZnO (sinc ogsaid) + 2NaOH (Sòidiam hydroxide) = Na2ZnO2 (sodium dioksotsinkat) + H2O (uisge).

Anns a 'chùis, ma tha an eileamaid an dà feartan an compound a leanas oxidation, a dùbailte (amphoteric) feartan as motha a follaiseach a' tachairt ann an eadar-mheadhanach oxidation ceum.

Mar eisimpleir faodar Chrome (CR) a. Tha an eileamaid seo a leanas oxidation stàitean: 3+, 2+ 6+. Ann an cùis trì bunaiteach agus searbh feartan a tha a chur an cèill mu ionann, fhad 'sa y Kr +2 bunaiteach air feartan buadhachadh, agus ann an Kr +6 - acid. Seo ath-bhualaidhean a dhearbhadh an aithris seo:

Kr + 2 → Crò (Chromium ogsaid +2), Kr (OH) 2 → CrSO4;
Kr + 3 → Cr2O3 (Chromium ogsaid +3), Kr (OH) 3 (Chromium hydroxide) → KCrO2 no Chromium sulphate Cr2 (SO4) 3;
Kr + 6 → CrO3 (Chromium ogsaid +6), H2CrO4 → K2CrO4.

Anns a 'chuid as motha de chùisean amphoteric oxides eileamaidean ceimigeach ann an staid oxidation +3 ann ann an meta fhoirm. Mar eisimpleir faodar ainmeachadh: Aluminium hydroxide ogsaid (foirmle ceimigeach AlO (OH) agus iarann metahydroxide (ceimigeach FeO (OH) foirmle) ...

Ciamar a tha amphoteric oxides?

1. Tha an dòigh as fhasa airson an ullachadh a th 'sileadh bho aqueous fuasgladh cleachdadh ammonium hydroxide, a tha lag bonn. Mar eisimpleir:
Al (NO3) 3 (aluminium nitrate) + 3 (H2OxNH3) (aqueous fuasgladh de Ammonia hydrate) = Al (OH) 3 (amphoteric ogsaid) + 3NH4NO3 (reaction air a coileanadh fo teas fichead ceum).
Al (NO3) 3 (aluminium nitrate) + 3 (H2OxNH3) (aqueous ammonium hydroxide) = AlO (OH) (amphoteric ogsaid) + 3NH4NO3 + H2O (reaction 'cluich aig 80 ° C)

Ann an iomlaid barail an t-seòrsa seo ann an cùis còrr alkali almain hydroxide cha precipitate. Tha seo mar thoradh air gu bheil an aluminium a 'dol a-steach dhan anion sgàth a dùbailte feartan: Al (OH) 3 (aluminium hydroxide) + OH- (còrr alkali) = [Al (OH) 4] - (aluminium hydroxide anion).

Eisimpleirean den t-seòrsa reaction:
Al (NO3) 3 (aluminium nitrate) + 4NaOH (còrr sodium hydroxide) = 3NaNO3 + Na (Al (OH) 4).
ZnSO4 (sinc sulfate) + 4NaOH (còrr sodium hydroxide) = Na2SO4 + Na2 (Zn (OH) 4).

Salann a tha air a stèidheachadh aig an aon àm, tha iom-fhillte choimeasgaidhean. Tha iad a 'gabhail a-steach iomadh-fhillte anions: (Al (OH) 4) - agus eile (Zn (OH) 4) mhaireas 2. Mar sin ghairm mi an t-salainn: Na (Al (OH) 4) - sodium tetragidroksoalyuminat, Na2 (Zn (OH) 4) - sodium tetragidroksotsinkat. Reaction bathar almain no sinc oxides leis an cruaidh alkali Tha an t-ainm eadar-dhealaichte: NaAlO2 - sodium dioksoalyuminat agus Na2ZnO2 - sodium dioksotsinkat.