Câu 1:
$n_e=\dfrac{It}{F}⇒3.n_{Al}=\dfrac{It}{F}\\⇒t=\dfrac{3.n_{Al}.F}{I}=\dfrac{3.10^6.96500}{27.30000}=99,28\ giờ$
$m_{Al_2O_3}=\dfrac{n_{Al}.102}{2}⇒m_{boxit}=3,778\ tấn$
Câu 2:
Anot: Xảy ra quá trình oxi hóa; Catot: Quá trình khử
$(-) Zn_{(r)},Zn^{2+}_{(aq)}||Cu^{2+}_{(aq)},Cu_{(r)} (+)$
Anot: $Zn\to Zn^{2+}+2e$
Catot: $Cu^{2+}+2e\to Cu$
$(-) Mg_{(r)},Mg^{2+}_{(aq)}||Ni^{2+}_{(aq)},Ni_{(r)} (+)$
Anot: $Mg\to Mg^{2+}+2e$
Catot: $Ni^{2+}+2e\to Ni$