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 $CO _2$.
$N{a_2}{B_4}{O_7}.10{H_2}O \xrightarrow{\Delta } X + NaB{O_2} + {H_2}O$
$X + C{r_2}{O_3}\xrightarrow{\Delta }Y$ (Green coloured)
$X$ and $Y$ are
In the electrolytic method of obtaining aluminium from purified bauxite, cryolite is added to the charge in order to
The Lewis acid character of boron tri halides follows the order:
A nonmetallic element of group $-13$, used in making bullet proof vests is extremely hard solid of black colour. It can exist in many allotropic forms and has unusually high melting point. Its trifluoride acts as Lewis acid towards ammonia. The element exhibits maximum covalence of four. Identify the element and write the reaction of its trifluoride with ammonia. Explain why does the trifluoride acts as a Lewis acid.