In a blast furnace,the highest temperature is in the:

Which of the following oxides can be reduced to the metal by heating it in a stream of hydrogen?

The cyanide complex of silver formed in the silver extraction in Mac-Arthur's Forrest cyanide process is

Which of the following statements is incorrect regarding the electrolysis of $Al_2O_3$ by the Hall-Heroult process?

Carbon reduction process is not commercially applicable for which of the following set of oxides to extract the respective metal?
$(I)$ $ZnO$,$(II)$ $Fe_2O_3$,$(III)$ $Al_2O_3$,$(IV)$ $SnO_2$,$(V)$ $MgO$

Iron obtained from blast furnace is: