Electrochemical hawa - "marasa aiki" zinc

Ana ɗaukar Zinc ƙarfe mai aiki. Matsakaicin ma'auni mara kyau yana nuna cewa zai yi ƙarfi tare da acid, yana kawar da hydrogen daga gare su. Bugu da ƙari, a matsayin ƙarfe na amphoteric, yana kuma amsawa tare da tushe don samar da gishiri mai mahimmanci. Duk da haka, zinc mai tsabta yana da matukar tsayayya ga acid da alkalis. Dalili shine babban tasirin juyin halittar hydrogen akan saman wannan karfe. Zinc ƙazanta yana haɓaka samuwar microcells na galvanic kuma, saboda haka, rushewar su.

Don gwajin farko za ku buƙaci: hydrochloric acid HCl, farantin zinc da waya ta jan karfe (hoto 1). Mun sanya farantin a cikin wani kwano na Petri cike da dilute hydrochloric acid (hoto 2), da kuma sanya jan karfe waya a kai (hoto 3), wanda HCl a fili ba ya tasiri. Bayan wani lokaci, hydrogen yana fitowa sosai a saman jan karfe (hotuna 4 da 5), ​​kuma kawai kumfa gas kaɗan ne kawai ake iya gani akan zinc. Dalili kuwa shi ne abin da aka ambata a sama na juyin halitta na hydrogen akan zinc, wanda ya fi na jan karfe girma. Ƙarfe da aka haɗa sun kai ga irin wannan damar game da maganin acid, amma hydrogen yana da sauƙi a rabu akan karfe tare da ƙananan ƙananan - jan karfe. A cikin kwayar galvanic da aka kafa tare da gajerun lantarki na Zn Cu, zinc shine anode:

(-) Bukatun: Zn⁰ → zinc²⁺ + 2e^-

kuma an rage hydrogen akan cathode na jan karfe:

(+) Katoda: 2h⁺ + 2e^- → N₂­

Haɗa duka daidaitattun matakan lantarki, muna samun rikodin halayen narkar da zinc a cikin acid:

Zinc + 2H⁺ → zinc²⁺ + H₂­

A gwaji na gaba, za mu yi amfani da maganin sodium hydroxide, farantin zinc da ƙusa na ƙarfe (hoto 6). Kamar yadda yake a cikin gwajin da ya gabata, an sanya farantin zinc a cikin maganin NaOH mai narkewa a cikin tasa na Petri kuma an sanya ƙusa akan shi (ƙarfe ba ƙarfe ba ne na amphoteric kuma baya amsawa tare da alkalis). Tasirin gwajin yayi kama - ana fitar da hydrogen akan saman ƙusa, kuma farantin zinc an rufe shi da ƴan kumfa gas kawai (hotuna 7 da 8). Dalilin wannan dabi'a na tsarin Zn-Fe kuma shine yawan ƙarfin juyin halitta na hydrogen akan zinc, wanda ya fi ƙarfin ƙarfe. Hakanan a cikin wannan gwaji, zinc shine anode:

(-) Bukatun: Zn⁰ → zinc²⁺ + 2e^-

kuma a kan baƙin ƙarfe cathode ruwa yana raguwa:

(+) Katoda: 2h₂ku +2e^- → N₂+ 2 ON^-

Ƙara duka equations a tarnaƙi da la'akari da matsakaicin amsawar alkaline, muna samun rikodin tsarin rushewar zinc bisa manufa (an samar da tetrahydroxyincide anions):

Zinc + 2 OH^- + 2H₂O → [Zn (ON)₄]^2- + H₂