Colour of the bead in borax bead test is mainly due to the formation of

Give reasons:

$(i)$ Conc. $HNO _{3}$ can be transported in aluminium container.

$(ii)$ $A$ mixture of dilute $NaOH$ and aluminium pieces is used to open drain.

$(iii)$ Graphite is used as lubricant.

$(iv)$ Diamond is used as an abrasive.

$(v)$ Aluminium alloys are used to make aircraft body.

$(vi)$ Aluminium utensils should not be kept in water overnight.

$(vii)$ Aluminium wire is used to make transmission cables.

Which of the following statements about the interstitial compounds is incorrect?

Which of the following is only acidic in nature

Given below are the statements about diborane.

$(a)$ Diborane is prepared by the oxidation of $\mathrm{NaBH}_{4}$ with $\mathrm{I}_{2}$.

$(b)$ Each boron atom is in sp $^{2}$ hybridized state.

$(c)$ Diborane has one bridged $3$ centre$-2-$electron bond.

$(d)$ Diborane is a planar molecule.

The option with correct statement(s) is :

Which of the following oxides is acidic in nature?