The number of aluminium ions present in 54 g of aluminium (atomic weight 27) is ___________.

The correct option is C $1.2\times {10}^{24}$
As per Mole concept,

$27g$ has $6.022\times {10}^{23}$ (Avogadro constant)

Hence $54g$ has $2\times 6.022\times {10}^{23}$ = $1.2\times {10}^{24}$