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.

(N/A) $(i)$ Concentrated $HNO_3$ reacts with aluminium to form a thin,non-reactive protective oxide layer on the surface,rendering the metal passive.
$(ii)$ $NaOH$ and $Al$ react to produce $H_2$ gas: $2Al + 2NaOH + 6H_2O \longrightarrow 2Na[Al(OH)_4] + 3H_2$. The pressure of the evolved $H_2$ gas helps clear blocked drains.
$(iii)$ Graphite has a layered structure held by weak van der Waals' forces,allowing layers to slide over each other,making it soft and slippery.
$(iv)$ Diamond has a rigid $3-D$ network of strong $sp^3$ covalent bonds,making it the hardest known substance,suitable for abrasives.
$(v)$ Aluminium is lightweight,possesses high tensile strength,and can be alloyed to improve mechanical properties,making it ideal for aircraft.
$(vi)$ Aluminium reacts with water to form a thin oxide layer. Over time,some $Al^{3+}$ ions may dissolve,which are harmful to health.
$(vii)$ Aluminium is lightweight,ductile,and a good conductor of electricity,making it a cost-effective alternative to copper for transmission cables.