$A$ large amount of energy is released during the formation of $Al_{2}O_{3}$,which is used in which of the following?

Explain silicon dioxide.

Which of the following elements exhibit metallic nature among $C$,$Si$,$Ge$,$Sn$,and $Pb$?

Which is an amphoteric oxide?

$A$ solid element $Y$ conducts electricity and forms two types of chlorides: $YCl_n$ (a colorless volatile liquid) and $YCl_{n-2}$ (a colorless solid). To which group does element $Y$ belong?

$A$ tetravalent element forms monoxide and dioxide with oxygen. When air is passed over the heated element $(1273 \ K)$,producer gas is obtained. The monoxide of the element is a powerful reducing agent and reduces ferric oxide to iron. Identify the element and write the formulas of its monoxide and dioxide. Write chemical equations for the formation of producer gas and the reduction of ferric oxide with the monoxide.