When aluminium hydroxide reacts with hydrochloric acid, it produces aluminium chloride as a neutral salt and (hydrogen gas/water).

Given below are two statements:
Statement $\mathrm{I}:$ Colourless cupric metaborate is reduced to cuprous metaborate in a luminous flame.

Statement $\mathrm{II}:$ Cuprous metaborate is obtained by heating boric anhydride and copper sulphate in a non-luminous flame.

In the light of the above statements, choose the most appropriate answer from the options given below.

Comprehension:

What is the compound A from the following observations?

Some observations related to an unknown inorganic substance A are presented below.

$1.$ A has a molecular weight of 267, and it is a yellowish-white deliquescent solid, and it sublimes on heating.

$2.$ A reacts violently with water, forming solution B.

$3.$ When a solution of ${\mathrm{NH}}_4\mathrm{Cl}$ and ${\mathrm{NH}}_4\mathrm{OH}$ is added to solution B, a white gelatinous precipitate is obtained.

$4.$ A sample of B also gives a curdy white precipitate C on addition of dilute nitric acid and silver nitrate solution. This white precipitate C readily dissolves when dilute ${\mathrm{NH}}_4\mathrm{OH}$ is added, though a gelatinous white precipitate D is formed in its place with excess ${\mathrm{NH}}_4\mathrm{OH}.$

$5.$ Precipitate D is filtered off and is dissolved in excess $\mathrm{NaOH}$ to give a clear solution E.

$6.$ When ${\mathrm{CO}}_2$ is passed through solution E, compound D is re-precipitated.

$7.$ Substance A unchanged in dry ether, when this solution is reacted with excess $\mathrm{LiH},$ it transforms to G.