Inorganic graphite is:

In borax,the number of $B-O-B$ links and $B-OH$ bonds present are,respectively:

In the following sets of reactants,which two sets best exhibit the amphoteric character of $Al_2O_3 \cdot xH_2O$?
Set $1$: $Al_2O_3 \cdot xH_2O_{(s)}$ and $OH^{-}_{(aq)}$
Set $2$: $Al_2O_3 \cdot xH_2O_{(s)}$ and $H_2O_{(l)}$
Set $3$: $Al_2O_3 \cdot xH_2O_{(s)}$ and $H^{+}_{(aq)}$
Set $4$: $Al_2O_3 \cdot xH_2O_{(s)}$ and $NH_{3(aq)}$

Which of the following is true for an element belonging to group $13$ of the periodic table?

Which of the following is an amphoteric hydroxide?

Consider the following reactions.
$Na_{2}B_{4}O_{7} \xrightarrow{\Delta} 2 X + Y$
$CuSO_{4} + Y \xrightarrow{\text{Non-Luminous flame}} Z + SO_{3}$
$2Z + 2X + \text{Carbon} \xrightarrow{\text{Luminous flame}} 2Q + Na_{2}B_{4}O_{7} + CO$
The oxidation states of $Cu$ in $Z$ and $Q$,respectively are: