Electrochemical rides - "Inactive" zinc

Zinc inoonekwa sesimbi inoshanda. Iyo yakaipa chiyero inogona kuratidza kuti ichaita zvechisimba nemaasidhi, ichibvisa hydrogen kubva kwavari. Mukuwedzera, sesimbi yeamphoteric, inopindirana nemabhesi kuti iite inoenderana nemunyu wakaoma. Zvisinei, zinc yakachena inopesana zvikuru neasidhi uye alkalis. Chikonzero chikuru repotential yehydrogen evolution pamusoro pesimbi iyi. Zinc tsvina inokurudzira kuumbwa kwegalvanic microcells uye, naizvozvo, kupera kwavo.

Pamuedzo wekutanga unoda: hydrochloric acid HCl, zinc plate uye copper wire (mufananidzo 1). Isu tinoisa ndiro muPetri ndiro yakazadzwa ne dilute hydrochloric acid (mufananidzo 2), uye kuisa waya yemhangura pairi (mufananidzo 3), iyo HCl zviri pachena haina kukanganisa. Mushure menguva yakati, hydrogen inosunungurwa zvakanyanya pamusoro pemhangura (mapikicha 4 ne5), uye zvishoma chete mabhubhu egasi anogona kuonekwa pane zinc. Chikonzero chataurwa pamusoro apa overvoltage yehydrogen evolution pane zinc, iyo yakakura kudarika pamhangura. Masimbi akabatanidzwa anosvika pakukwanisa kumwechete maererano nemhinduro yeasidhi, asi hydrogen inoparadzaniswa nyore nyore pasimbi ine yakaderera overvoltage - mhangura. Mune yakaumbwa galvanic cell ine shorted Zn Cu maelectrodes, zinc ndiyo anode:

(-) Zvinodiwa: Zn⁰ → zingi²⁺ + 2e^-

uye hydrogen inoderedzwa pane cathode yemhangura:

(+) Katoda: 2h⁺ + 2e^- → H₂­

tichiwedzera pamwe chete maequation ese e electrode maitiro, tinowana rekodhi yemaitiro ekuparara kwe zinc mu acid:

Zingi + 2H⁺ → zingi²⁺ + H₂­

Mumuedzo unotevera, tichashandisa sodium hydroxide solution, zinc plate uye chipikiri chesimbi (mufananidzo 6). Sezvakaitwa mukuedza kwekare, ndiro ye zinc inoiswa mune yakasvibiswa NaOH mhinduro muPetri dish uye mbambo inoiswa pairi (simbi haisi amphoteric simbi uye haina kuita nealkalis). Mhedzisiro yekuedza yakafanana - haidrojeni inoburitswa pamusoro pembambo, uye zinc ndiro yakafukidzwa nemabhuru mashoma egasi (mapikicha 7 ne8). Chikonzero chemaitiro aya eZn-Fe system zvakare kuwanda kwehydrogen evolution pane zinc, iyo yakakura kudarika iron. Zvakare mukuyedza uku, zinc ndiyo anode:

(-) Zvinodiwa: Zn⁰ → zingi²⁺ + 2e^-

uye pane iron cathode mvura inoderedzwa:

(+) Katoda: 2h₂O +2e^- → H₂+ 2ON^-

Kuwedzera ese ari maviri equation pamativi uye tichifunga nezve alkaline reaction medium, tinowana rekodhi yezinc disolution process in musimboti (tetrahydroxyincide anions inogadzirwa):

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