When metal $X$ is treated with sodium hydroxide, a white precipitate $(A)$ is obtained, which is soluble in excess of $NaOH$ to give soluble complex $(B)$. Compound $(A)$ is soluble in dilute $HCl$ to form compound $(C)$. The compound $(A)$ when heated strongly gives $(D)$, which is used to extract metal. Identify $(X), (A), (B), (C)$ and $(D)$. Write  suitable equations to support their identities. 

Which elements of group $13$, except $B$, can form tetrahedral and octahedral complex in aqueous medium ?

The incorrect statement from the following for borazine is:

The ionic carbide is

Outermost electronic configuration of a group $13$ element, $E$, is $4 \,\mathrm{~s}^{2}, 4 p^{1}$. The electronic configuration of an element of $p$-block period-five placed diagonally to element, $E$ is :