Te Mārama ki te Hikohiko me ngā Tauira
Te Mārama ki te Hikohiko
Ko te hikohiko he tukanga matū e whakamahi ana i te iahiko tika (DC) hei akiaki i tētahi tauhohenga matū kore-tūpono. Ko te kupu "hikohiko" i ahu mai i ngā kupu Kariki "electro," ko tōna tikanga he hiko, me te "lysis," ko tōna tikanga he wehenga. Arā, ko te hikohiko te tukanga wehewehe i tētahi matū ki ōna huānga mā te whakamahi i te hiko.
Kāore ngā tauhohenga matū e puta ana i roto i te hikohiko e puta noa mai ana, ā, me whai pūngao hiko kia puta ai. He maha ngā whakamahinga o te hikohiko i roto i ngā ahumahi maha, tae atu ki te whakarewa, te hanga matū, me te whakamahine whakarewa.
Te Mātāpono Mahi o te Hikohiko
E toru ngā wāhanga matua e hiahiatia ana mō te hikohiko: he hikohiko, he katote, me te anode.
1. Ko ngā irahiko he matū kei roto ngā iona kore utu, ā, ka taea te kawe i te iahiko. Ko ngā irahiko he wai, he otinga rānei kei roto ēnei iona.
2. Ko te katote te irahiko (kaiārahi hiko) te wāhi e puta ai te whakaiti, arā, te tangohanga o ngā irahiko e ngā katote, e ngā ngota rānei.
3. Ko te anode te irahiko e puta ai te waikura, arā, te tukunga o ngā irahiko e ngā katote, e ngā ngota rānei.
Ina rere te iahiko i roto i te irahiko, ka neke ngā iona o te irahiko ki te irahiko he rerekē te utu. Ka neke ngā iona pai (ngā kationa) ki te katote, ko ngā iona kino (ngā aniona) ka neke ki te anote. Ka puta he tauhohenga matū i ngā irahiko e rua.
Ngā Tauhohenga Redox i roto i te Hikohiko
Ko te tukanga hikohiko he tauhohenga redox (whakaiti-waikura). I te cathode, ka puta he tauhohenga whakaiti, ka mimitihia e ngā irahiko ngā irahiko hei hanga i tētahi matū hou. I te anode, ka puta he tauhohenga waikura, ka tukuna e ngā irahiko ngā irahiko hei hanga i tētahi matū hou.
Tauira o te Whārite Tauhohenga Hikohiko
He tauira māmā noa iho ko te hikohiko o te wai (H₂O). Anei ngā mahi o te tauhohenga e puta ana:
1. Te Whakakāwaitanga o te Wai:
\[2H₂O(l) \perematau 2H⁺(aq) + 2OH⁻(aq)\]
2. Tauhohenga i te Cathode:
\[2H⁺(aq) + 2e⁻ \perematau H₂(g)\]
3. Tauhohenga i te Anode:
\[4OH⁻(aq) \perematau O₂(g) + 2H₂O(l) + 4e⁻\]
I te nuinga, ka puta he hau hauwai (H₂) i te cathode me te hau hāora (O₂) i te anode i tēnei tauhohenga hiko wai.
Ngā Tauira o te Whakamahinga o te Hikohiko
1. Te Whakamahinga Konganuku
Ka whakamahia te hikohiko hei pure i ngā konganuku, pērā i te parahi. I roto i tēnei tukanga, ka mahi tētahi wahi parahi poke hei anode, ā, ka mahi tētahi wahi parahi parakore hei cathode. Ko te hikohiko e whakamahia ana he otinga parahi whanariki (CuSO₄).
Ko te tukanga e whai ake nei:
– I te anode, ka waikurahia te parahi poke ki ngā katote parahi (II) ka rewa ki roto i te electrolyte:
\[Cu(s) \rightarrow Cu²⁺(aq) + 2e⁻\]
– Kātahi ka neke atu ēnei iona parahi ki te katote, ka whakaitihia ki reira ka piri ki te katote:
\[Cu²⁺(aq) + 2e⁻ \perematau Cu(s)\]
Ko te mutunga iho he parahi parakore ka whakatakotoria ki runga i te katote, ā, ka heke haere te parahi poke ki runga i te anode.
2. Te whakaputanga o te hau chlorine me te konutai hydroxide
Ko te tukanga chlor-alkali he tikanga e whakamahia ana hei whakaputa i te hau chlorine (Cl₂) me te konutai hauwai (NaOH) mā te hikohiko o te otinga konutai hauwai (NaCl).
Kei roto i te tukanga ngā tauhohenga e whai ake nei:
– I te katote, ka whakaitihia ngā iona konutai (Na⁺) me te wai hei whakaputa i te hau hauwai (H₂) me ngā iona hauwaiwai (OH⁻):
\[2H₂O(l) + 2e⁻ \perematau H₂(g) + 2OH⁻(aq)\]
– I te anode, ka waikuratia ngā katote kōraira (Cl⁻) hei whakaputa hau kōraira (Cl₂):
\[2Cl⁻(aq) \perematau Cl₂(g) + 2e⁻\]
Ko te mutunga iho he hau hauwai i te cathode me te hau chlorine i te anode, me te otinga hauwai konutai i hangaia i roto i te electrolyte.
3. Te whakakikorua hiko
Ko te whakakikorua hiko he tukanga paninga i tētahi konganuku ki tētahi atu mā te whakamahi i te hikohiko. Ko ngā tauira noa ko te whakakikorua i ngā whakapaipai me ngā taonga o te whare ki te hiriwa, ki te koura rānei.
Ko te tukanga whakakikorua hiko ka penei:
– Ko te mea hei paninga (hei tauira, he mowhiti) ka whakamahia hei katote.
– Ka whakamahia he konganuku whakakikorua (hei tauira, te hiriwa, te koura rānei) hei anode.
– Ko te irahiko he otinga kei roto he katote whakarewa paninga (hei tauira, te otinga hiriwa hauota AgNO₃).
I te wā o te electrolysis, ka rewa ngā katote konganuku mai i te anode ki roto i te electrolyte, kātahi ka neke ki te cathode, ka whakaitihia, ka piri ki te mea hei paninga.
4. Te Hanga Konumohe
Ka whakamahia hoki te hikohiko i roto i te hanga konumohe mai i te konganuku bauxite i roto i tētahi tukanga e mōhiotia ana ko te tukanga Hall-Héroult.
– Ko te bauxite, he nui te waikura konumohe (Al₂O₃), ka hurihia tuatahitia hei alumina parakore (Al₂O₃).
– Kātahi ka rewa te alumina ki roto i te cryolite rewa (Na₃AlF₆) ka whakamātauria ki te hiko i roto i tētahi pūtau motuhake.
– I te katote, ka whakaitihia ngā katote konumohe:
\[Al³⁺ + 3e⁻ \rightarrow Al\]
– I te anode, ka waikurahia te hāora mai i te waikura konumohe, ā, ka hanga he hau hāora:
\[2O²⁻ \rightarrow O₂ + 4e⁻\]
Whakamutunga
He hangarau hikohiko he nui ngā whakamahinga i roto i te ahumahi me te oranga o ia rā. Mai i te whakamahine whakarewa me te whakaputa i ngā matū nui pēnei i te chlorine me te konutai hauwai, ki ngā tikanga whakakikorua hei whakapaipai me te tiaki i ngā mea whakarewa, he whānui, he kanorau hoki ngā painga o te hikohiko.
He mea nui te mārama ki ngā mātāpono taketake o te hikohiko hei tūhura i ngā momo tikanga me ngā tono ka taea te whakamahi i roto i ngā momo rāngai hangarau me ngā ahumahi. I te whanaketanga tonu o te hangarau, e tūmanakohia ana ka whanake tonu te tukanga hikohiko, ā, ka nui ake ngā painga mō te tangata.
