Which of the following pair of ores cannot be converted into corresponding metals by pyrometallurgy ?

The anode mud in the electrolytic refining of silver contains

Which of the following is not an ore of magnesium?

Sulphide ion is soft base and its ores are common for metals.

$(a)$ ${Pb}$      $(b)$ ${Al}$     $(c)$ ${Ag}$     $(d)$ ${Mg}$  

Choose the correct answer from the options given below :

The maximum temperature $1550\,^oC$ is obtained in the ……… region of the blast furnace used in the extraction of iron.