Dzidziso yaLewis yeAcid-Base: Kunzwisisa Kwakakura Uye Kwakawanda
Pendauluan
Isaac Newton akamboti aigona kuona zvakawanda nekumira pamafudzi ehofori, uye mukemistri, misimboti mikuru yatinogamuchira nhasi yakavakirwa pabasa remasayendisiti ekare. Imwe yeiyi budiriro yakakosha yaive dzidziso yaLewis yeacids and bases, yakatangwa naGilbert N. Lewis muna 1923. Dzidziso iyi yakarerutsa uye yakawedzera pfungwa dzeacids and bases, zvichiita kuti zvive nyore kunzwisisa nekushandisa mukemistri yemazuva ano.
Sesumo, ngatitarisei dzidziso dzeacid nebase dzakataurwa pamberi paLewis. Kutanga, dzidziso yeArrhenius acid-base inoti acid imusanganiswa unogona kuwedzera huwandu hwehydrogen ions (H⁺) mumusanganiswa, nepo base iri musanganiswa unogona kuwedzera huwandu hwehydroxide ions (OH⁻). Gare gare, nzanga yesainzi yakagamuchira dzidziso yeBronsted-Lowry acid-base , iyo yakawedzera tsananguro iyi nekutaura kuti acid iproton (H⁺) donor uye base iproton acceptor. Zvisinei, tsananguro dzedzidziso dzese dzine miganhu, kunyanya patinofunga nezvemaitiro emakemikari asingabatanidzi maproton kana hydroxide ions.
Tsanangudzo neMitemo Nheyo yeAcid Sekureva kwaLewis
Gilbert N. Lewis akaona kusakwana uku uye akapa tsananguro yakajairika yemaacids nemabases. Mudzidziso yaLewis yeacid-base, acid inotsanangurwa se electron-pair acceptor, nepo base iri electron-pair donor. Tsananguro iyi inopfuura mhinduro dzemvura uye maitiro ane chekuita nemaproton, zvichibvumira kunzwisisa kwakakura kwemarudzi akasiyana-siyana emakemikari.
Muenzaniso wepfungwa iyi ndeyekuita pakati peammonia (NH3) neboric acid (BF3). Muchiitiko ichi, NH3 inoshanda seLewis base nekuti inopa electron pair paatomu yayo yenitrogen kuatomu yeboron isina electron iri muBF3, iyo inoshanda seLewis acid. Kubatana pakati peelektron pair yeLewis base neelectron acceptor yeLewis acid kunoita kuti pave neadduct complex yakasimba.
Chimwe Chinhu Chinokosha cheLewis Theory
Chimwe chezvakasimba zvedzidziso yaLewis kugona kwayo kutsanangura maitiro asingakwanise kutsanangurwa nedzidziso dzaArrhenius kana Bronsted-Lowry. Izvi zvinosanganisira maitiro asingabatanidzi mapurotoni zvakajeka. Semuenzaniso, mune akasiyana-siyana maitiro emakemikari e-organometallic uye coordination, kudyidzana pakati simbi dzekuchinja uye ma ligand zvinogona kutsanangurwa zviri nyore uchishandisa pfungwa yeLewis acids and bases.
1. Pfungwa yeOrbitals nemarudzi ekudyidzana
Chinhu chakakosha muLewis acid-base theory kunzwisisa ma orbitals uye mhando dzekudyidzana pakati pemaacids nemabases. Semuenzaniso, ma d-orbitals e transition metals anowanzoita basa rekubatana nema ligands anoshanda seLewis bases. Kudyidzana uku ndiko kunotungamira pakuumbwa kwema coordination complexes, ayo akakosha mukushandiswa kwemakemikari akawanda akadai se homogeneous catalysis uye supramolecular chemistry.
2. Kugadzikana kweMidziyo
Kugadzikana kwema "adduct complexes" anoumbwa pakati peLewis acids nema "bases" kunogona kuongororwa kuburikidza nema "parameters" akasiyana-siyana akadai se "geometric compatibility", "electrostatic interaction energy", uye "polarity". Semuenzaniso, zvinhu zvakaita se "electron affinity" uye "three-dimensional structure" yemorekuru zvinogona kukanganisa kuti "electron pair" inogona kugamuchirwa kana kupihwa zvakasimba sei.
3. Zvikumbiro muCatalysis
Dzidziso hwaro hweasidhi Maasidhi eLewis anoitawo basa rakakosha mukugadzira ma "catalysis", kunyanya mukugadzira ma "acid-base catalysis" akasiyana uye akafanana. Ma "catalysts" anokurumidza kuita zvinhu nekupa dzimwe nzira dzine simba shoma rekuita kuti zvinhu zvishande. Ma "transition metal catalysts" mazhinji anogona kushanda se "Lewis acids" kuti aite kuti zvinhu zvishande kuburikidza nekugamuchira ma "electron pair". Semuenzaniso, mukugadzira ma "hydrogenation catalysis", simbi dzakadai seplatinum kana palladium dzinogona kubatsira pakusunga nekubatidza ma "hydrogen molecules".
Kuenzanisa uye Kuganhurirwa kweLewis Theory
Kunyangwe dzidziso yaLewis inonzi acid-base ichipa ruzivo rwakakura, haitsivi Arrhenius naBronsted-Lowry zvachose. Dzidziso yega yega ine simba rayo uye mashandisirwo ayo mukutsanangura mamwe marudzi ekuita. Semuenzaniso, dzidziso yaArrhenius inobatsira zvikuru pakunzwisisa hunhu hwe electrolytes mumhinduro ine mvura, nepo dzidziso yeBronsted-Lowry ichinyanya kushanda kune acid-base reactions muzvinhu zvisiri zvemvura kana gas phase.
Chimwe chinokanganisa dzidziso yaLewis ndechekuti tsananguro dzayo dzemaacids nemabases dzakafanana zvekuti dzimwe nguva zvakaoma kutsanangura zvakananga mumamiriro ezvinhu chaiwo pasina rubatsiro rwepfungwa dzakadzama dzemakemikari dzakadai se quantum chemistry kana spectroscopic analysis. Kudzidzisa nekushandisa dzidziso yaLewis kunowanzoda mienzaniso chaiyo uye ongororo yakadzama kuti ibudirire zvechokwadi.
Mhedziso uye Mhedzisiro
Dzidziso yeLewis acid-base inowedzera kunzwisisa kwedu kudyidzana kwemakemikari netsananguro dzinochinjika uye mashandisirwo akafara. Nekutsanangura maacid sema electron-pair acceptors uye mabhesi sema electron-pair donor, dzidziso iyi inovhura mativi matsva mukunzwisisa mhando dzakasiyana dzema chemical reactions. Izvi zvinosanganisira ma reactions asingabatanidzi ma hydrogen ions kana ma hydroxide ions, akadai se coordination complexes uye catalytic reactions mu organometallic chemistry.
Zvose, mipiro yaGilbert N. Lewis kudzidziso iyi haina kungosimbisa hwaro hwekemikari chete asiwo yakapa chishandiso chinokosha chekuwedzera kuferefeta kwesainzi. Kunzwisisa kwakadzama kwedzidziso iyi kunotibatsira kunzwisisa zviitiko zvakaoma zvemakemikari uye kunokurumidza kuvandudza zvinhu zvitsva muminda yakaita semishonga, zvinhu zvesainzi, uye tekinoroji yesimba. Saka, nekuziva kukosha kwedzidziso iyi yeacid-base , tinogona kuinzwisisa nekuishandisa muzvidzidzo zvakawanda uye mashandisirwo ayo.
