asked in 科學化學 · 1 decade ago

普通化學問題 電化學

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  • 1 decade ago
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    Consider the following half-reactions and voltages.

    2H+(aq)+2e--->H2(g) E°= 0.0V

    Li+(aq)+1e--->Li(s) E°=-3.05V

    O2(g)+4H+(aq)--->2H2O(l) E°= 1.23V

    F2(g)+2e--->2F-(g) E°= 2.87V

    what is the product produced at the cathode when a current is passed through an aqueous solution of LiF?

    (A)Lithium [Li(s)](B)fluorine [F2(g)] (C) hydrogen [H2(g)] (D)oxygen [O2(g)] (E)none of the above[X]

    在陰極應為還原反應(得電子反應)

    若是考慮氧化還原半反應電位的關係

    電位為正時,會有自發性反應

    電位為負時,則需要外加能量使其發生

    在本題中,在LiF溶液會分解為Li+ 陽離子與F-陰離子

    陰極有可能的還原半反應如下:

    2H+(aq)+2e--->H2(g) E°= 0.0V----(1)

    Li+(aq)+1e--->Li(s) E°=-3.05V---(2)

    以第一式的電位較高,故在陰極會發生的半反應亦如是。

    所以答案為(3)H2(g)

  • 1 decade ago

    看樣子應該是給了一堆還原電位然後問你電解LiF水溶液時陰極會產生什麼東西

    還原電位越大越先生成+陰極發生還原反應

    所以呢

    答案"應該"是(C)...

    Source(s): 高中化學判斷...........
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