Which of the following metals is the most reactive?

Generally,non-metals are not lustrous. Which of the following non-metal is lustrous?

Account for the following:
$(a)$ Aluminium is more reactive than iron,but its corrosion is less than iron.
$(b)$ Hydrogen gas is not evolved when zinc metal reacts with dilute $HNO_3$.
$(c)$ Carbon is not used for reducing aluminium from aluminium oxide.

How many atoms of sulfur are present in one molecule of sulfur?

An element forms an oxide $A_{2}O_{3}$ which is acidic in nature. Identify $A$ as a metal or non-metal.

Name two metals which react with dilute $HNO_{3}$ to evolve $H_{2}$ gas.