Which of the following ores is in the form of oxide?

Which metal does not react with oxygen even at high temperatures?

What change occurs in the concentrated ore during the roasting process?

$A$ metal $M$ does not liberate hydrogen from acids but reacts with oxygen to give a black coloured product. Identify $M$ and the black coloured product,and also explain the reaction of $M$ with oxygen.

Why is sodium chloride soluble in water but not soluble in kerosene?

Which of the following reactions is called roasting?