Which gas has a pungent smell that causes choking and coughing?

Which of the following metals is the least reactive?

$A$ metal $M$ forms an oxide having the formula $M_{2}O_{3}$. It dissolves in both dilute sulphuric acid and dilute sodium hydroxide solution. Identify the metal and write the chemical equations for the reactions involved.

Which metal ore can be concentrated by the magnetic separation method?

Which ore is concentrated by the froth flotation process?

Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same?
$(i)$ Good thermal conductivity
$(ii)$ Good electrical conductivity
$(iii)$ Ductility
$(iv)$ High melting point