Nā holo uila - "Inactive" zinc
Manaʻo ʻia ʻo Zinc he metala ikaika. Hōʻike ka manaʻo maʻamau maikaʻi ʻole e hana ikaika ia me nā waikawa, e hoʻoneʻe i ka hydrogen mai ia mau mea. Eia kekahi, ma ke ʻano he metala amphoteric, hana pū me nā kumu e hana i nā paʻakai paʻakikī e pili ana. Eia naʻe, kūpaʻa loa ka zinc maʻemaʻe i nā waikawa a me nā alkali. ʻO ke kumu ka repotential nui o ka hoʻololi hydrogen ma ka ʻili o kēia metala. Hoʻoikaika ka Zinc impurities i ke kūkulu ʻana i nā microcells galvanic a, no laila, hoʻopau lākou.
No ka hoʻāʻo mua e pono ai ʻoe: hydrochloric acid HCl, zinc plate a me ke kelepona keleawe (kiʻi 1). Hoʻokomo mākou i ka pā i loko o kahi pā Petri i hoʻopiha ʻia me ka dilute hydrochloric acid (photo 2), a kau i ke kaula keleawe ma luna (photo 3), ʻaʻole maopopo i ka HCl. Ma hope o kekahi manawa, hoʻokuʻu ikaika ʻia ka hydrogen ma luna o ka ʻili keleawe (nā kiʻi 4 a me 5), a he liʻiliʻi wale nō nā ʻōpū kinoea hiki ke ʻike ʻia ma ka zinc. ʻO ke kumu ka overvoltage o ka hydrogen evolution i ʻōlelo ʻia ma luna o ka zinc, ʻoi aku ka nui ma mua o ke keleawe. Hiki i nā metala i hui pū ʻia i ka mana like e pili ana i ka hopena waika, akā ʻoi aku ka maʻalahi o ka hoʻokaʻawale ʻana o ka hydrogen ma ka metala me kahi overvoltage haʻahaʻa - keleawe. I loko o ke kelepona galvanic i hana ʻia me nā electrodes Zn Cu pōkole, ʻo ka zinc ka anode:
(-) Pono: Zn0 → zinc2+ +2e-
a ua hoemiia ka hydrogen ma ka cathode keleawe:
(+) Katoda: 2h+ +2e- → N2
e hoʻohui pū i nā hoohalike ʻelua o nā kaʻina hana electrode, loaʻa iā mākou kahi moʻolelo o ka hopena o ka dissolution zinc i loko o ka waikawa:
Zinc + 2N+ → zinc2+ + H2
I ka ho'āʻo aʻe, e hoʻohana mākou i kahi solution sodium hydroxide, kahi pā zinc a me kahi kui kila (kiʻi 6). E like me ka hoʻokolohua mua, hoʻokomo ʻia kahi pā zinc i loko o kahi solution NaOH dilute i loko o kahi pā Petri a kau ʻia kahi kui ma luna o ia mea (ʻaʻole he metala amphoteric ka hao a ʻaʻole hoʻololi me ka alkali). Ua like ka hopena o ka hoʻokolohua - ua hoʻokuʻu ʻia ka hydrogen ma ka ʻili o ke kui, a ua uhi ʻia ka pā zinc me ka liʻiliʻi o nā ʻōpū kinoea (nā kiʻi 7 a me 8). ʻO ke kumu o kēia ʻano o ka ʻōnaehana Zn-Fe ʻo ia hoʻi ka overvoltage o ka evolution hydrogen ma ka zinc, ʻoi aku ka nui ma mua o ka hao. Eia kekahi ma kēia hoʻokolohua, ʻo ka zinc ka anode:
(-) Pono: Zn0 → zinc2+ +2e-
a ma ka hao cathode ua hoemiia ka wai.
(+) Katoda: 2h2O + 2e- → N2+ 2ON-
Hoʻohui i nā hoʻohālikelike ʻelua ma nā ʻaoʻao a me ka noʻonoʻo ʻana i ka medium reaction alkaline, loaʻa iā mākou kahi moʻolelo o ke kaʻina hana hoʻoheheʻe zinc ma ke kumu (ua hoʻokumu ʻia nā anion tetrahydroxyincide):
Zinc + 2ON- + 2H2O → [Zn(OH)4]2- + H2
