Identify the correct statements about the anomalous behaviour of Boron:
$I$. Boron trihalides can form dimeric structures.
$II$. Boron shows $+1$ as a stable oxidation state.
$III$. Maximum covalency of Boron is four.
$IV$. Boron does not form $BF_{6}^{3-}$ ion.

Explain the physical and chemical properties of borax.

In the reaction $B_2H_6 + 2KOH + 2X \to 2Y + 6H_2$,$X$ and $Y$ are respectively

Is boric acid a protic acid? Explain.

$A$ compound $(A)$ of boron reacts with $NMe_3$ to give an adduct $(B)$ which on hydrolysis gives a compound $(C)$ and hydrogen gas. Compound $(C)$ is an acid. Identify the compounds $A, B$ and $C$. Give the reactions involved.

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.