Naphthalene is a/an

Soldiers of Napoleon's army while at the Alps during a freezing winter suffered a serious problem regarding the tin buttons of their uniforms. White metallic tin buttons got converted to grey powder. This transformation is related to

Which of the following can act as a $p-$type semiconductor?

The existence of a substance in more than one solid modification is known as

Which of the following dopants is used in germanium to form $n-$type semiconductor?

An example of a network solid is