Purification of aluminium done by electrolytic refining is known as

Aluminium chloride in acidified aqueous solution forms an ion having geometry

For purification of alumina, the modern processes most useful when $(i)$ the impurity present is a lot of iron oxides and $(ii)$ the impurity present is a lot of silica, are

Which of the following sublimes on heating?

The electrochemical extraction of aluminum from bauxite ore involves.

$(A)$ the reaction of $Al _2 O _3$ with coke ($C$) at a temperature $>2500^{\circ} C$.

$(B)$ the neutralization of aluminate solution by passing $CO _2$ gas to precipitate hydrated alumina $\left( Al _2 O _3 .3 H _2 O \right)$

$(C)$ the dissolution of $Al _2 O _3$ in hot aqueous $NaOH$.

$(D)$ the electrolysis of $Al _2 O _3$ mixed with $Na _3 AlF _6$ to give $Al$ and $CO _2$.

Below are two statements, one labeled as Assertion $(A)$ and the other as Reason $(R):$

Assertion $(A)$: Among group $13$ elements, boron's melting point is unusually high $(2453 \mathrm{~K})$.

Reason $(R):$ Solid boron has a strong crystalline lattice.

In the context of the above statements, choose the correct answer from the following options: