Vim li cas tsis tuaj yeem zinc tuag-castings rau hluav taws xob cua sov tub rau hauv qhov kub thiab muaj zog alkali thaum degreasing?

Vim li cas tsis tuaj yeem zinc tuag-castings rau hluav taws xob cua sov tub rau hauv qhov kub thiab muaj zog alkali thaum degreasing?

Teb: Vim zinc yog cov hlau amphoteric, nws yooj yim soluble hauv acids thiab alkalis. Zinc yaj sai sai hauv qhov kub thiab txias muaj zog alkali, yog li zinc tuag castings tsis tuaj yeem muab tso rau hauv qhov kub kub muaj zog alkali rau kev tshem tawm roj.

54. Nyob rau hauv ib tug tej yam nickel plating tov, tag nrho cov tam sim no ntws mus rau hauv lub plating da dej yog 400A, thiab lub energization lub sij hawm yog 15 feeb. Yog tias qhov ua tau zoo tam sim no yog 95 feem pua, pes tsawg grams ntawm cov hlau npib tsib xee yuav yog eutectoid?

Teb: Raws li txoj cai ntawm electrolysis, qhov hnyav ntawm txheej (m) yuav tsum yog:

m=K? I? t? η k

Raws li cov qauv saum toj no, electrochemical sib npaug K ntawm nickel yog 1.095 grams ib ampere? Teev.

Nyob rau hauv cov xwm txheej saum toj no, 104 grams ntawm hlau npib tsib xee tuaj yeem ua rau nag

55. Thaum ntsuas qhov ua tau zoo tam sim no ntawm cov tshuaj chromium plating, qhov hnyav ntawm cov xim hlau chromium precipitated ntawm cathode tom qab 2 teev ntawm qhov tam sim no ntawm 20A yog 1.8 grams. Xam qhov tam sim no efficiency ntawm cov tshuaj chromium plating?

Teb: Raws li txoj cai ntawm electrolysis, qhov hnyav ntawm txheej (m) yuav tsum yog:

η k {{0}}K? kuv? t? Raws li cov qauv saum toj no, electrochemical sib npaug K ntawm hexavalent chromium pom tias yog 0.324 grams ib ampere? Teev.

Raws li cov xwm txheej saum toj no, cathode tam sim no ua haujlwm ntawm cov tshuaj chromium plating yog 13.9 feem pua

56. Vim li cas qhov kev txo qis ntawm dichromate rau trivalent chromium ntawm cathode nres nyob rau hauv ib qho instant tsis muaj catalytic anions?

Teb: Thaum tsis muaj catalytic anions nyob rau hauv cov tshuaj chromium plating, thaum lub tam sim no qhib, hydrogen gas yog precipitated ntawm lub cathode thiab ib nrab txo rau trivalent chromium. Vim yog nag lossis daus ntawm hydrogen, pH ntawm thaj chaw cathode nce, thiab trivalent chromium tam sim ntawd tsim ib qho yooj yim chromium chromate [Cr (OH) 3Cr (OH) CrO4] zaj duab xis ntawm cathode. Nws yog ib tug zoo them dispersed colloid uas kaw lub cathode nto. Cov zaj duab xis no nruj heev thiab tsuas yog tso cai rau hydrogen ions dhau mus, ua rau cov tshuaj tiv thaiv hauv qab no 2H ntxiv rau 2e → H2 ↑. Txawm li cas los xij, dichromate tsis tuaj yeem dhau los ntawm zaj duab xis no. Yog li ntawd, thaum tsis muaj catalytic anions hauv cov tshuaj chromium plating, cov tshuaj tiv thaiv ntawm dichromate txo rau trivalent chromium ntawm cathode nres nyob rau hauv ib qho instant.