Which of the following statements is correct ? (i) Copper is extracted by hydrometallury from low grade ores. (ii) In electrolytic reductionof alumina , graphite is acting as anode and steel vessel with lining of carbon acts as cathode. (iii) In Hall-Heroult process, aluminium is obtained at anode and COand CO_(2) are produce at cathode

Which of the following statements is correct ? (i) Copper is extracted

1.	Which of the following statements is correct ? (i) Copper is extracted by hydrometallury from low grade ores. (ii) In electrolytic reductionof alumina , graphite is acting as anode and steel vessel with lining of carbon acts as cathode. (iii) In Hall-Heroult process, aluminium is obtained at anode and COand CO_(2) are produce at cathode
Answer» (i) only (i) and (II) only (ii) and (iii) only All of these Solution :In Hall-Heroult process, At cathode : `Al_("(MELT)")^(3+)+ 3e^(-) to Al_((L))` At anode : `C_((s)) + O_("(melt)")^(2-) to CO_(2(g)) + 4e^(-)` `C_((s)) + 2O_("(melt)")^(2-) to CO_(2(g)) + 4e^(-)`