An aqueous solution of borax is

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.

The incorrect stability order of $+3$ and $+1$ states of $13^{th}$ group elements (boron family) is

Identify the correct statements from the following :
$I$. $Ga_2O_3$ is an amphoteric oxide.
$II$. The dimer of aluminium chloride has three $Al-Cl-Al$ bridge bonds.
$III$. Boron is a very hard refractory solid of high melting temperature.

Consider the following reactions:
$(a) \ B_2H_6 + 6H_2O \to 2H_3BO_3 + 6H_2$
$(b) \ B_2H_6 + 6CH_3OH \to 2B(OCH_3)_3 + 6H_2$
$(c) \ B_2H_6 + 3Cl_2 \to 2BCl_3 + 6HCl$
$(d) \ B_2H_6 + 6CH_3COOH \to 2B(OCOCH_3)_3 + 6H_2$
Identify the incorrect statement about the product$(s)$.

$H_3BO_3$ is