"Chile saltpetre" is an ore of

Sulphide ion is a soft base and its ores are common for metals. Which of the following metals commonly occur as sulphide ores?
$(a)$ $Pb$ $(b)$ $Al$ $(c)$ $Ag$ $(d)$ $Mg$
Choose the correct answer from the options given below:

$FeS_2$ is also known as $'$Fools gold$'.$

Which of the following statements is incorrect?

What are the oxidation states of iron and chromium in chromite ore,respectively?

Aluminium is the most abundant metal in the Earth's crust,yet it is primarily obtained from bauxite because: