In the metallurgy of aluminium, cryolite is mixed in the molten state because it

Aluminium chloride exists as dimer, $Al_2Cl_6$ in solid state as well as in soluiton of non-polar solvents such as $C_6H_6.$ When dissolved in water it gives :

In $B_2H_6$

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

Complete the following chemical equations :

$Z + 3LiAl{H_4} \to X + 3LiF + 3Al{F_3}$

$X + 6{H_2}O \to Y + 6{H_2}$

$3X + 3{O_2}\xrightarrow{\Delta }{B_2}{O_3} + 3{H_2}O$

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.