Which of the following allotropes of phosphorus is the most stable,has a graphite-like structure,and is a conductor of electricity?

Which of the following mixtures of two gases in equimolar amounts will produce a blue liquid at $-30\,^oC$?

White phosphorus contains

$A$ metal $(X)$ dissolves in both dilute $HCl$ and dilute $NaOH$ to liberate $H_2$ gas. Addition of $NH_4Cl$ and excess $NH_4OH$ to an $HCl$ solution of $(X)$ produces $(Y)$ as a precipitate. $(Y)$ is also produced by adding $NH_4Cl$ to the $NaOH$ solution of $(X)$. The species $(X)$ and $(Y)$,respectively,are:

When bauxite powder is mixed with coke and heated with nitrogen at $2075 \ K$,carbon monoxide and $x$ are formed. Which gas is produced when $x$ reacts with water?

Which of the following order is incorrect?