Calculate concentration
$c = \frac{n}{V}$
$m = n*M$

$1L = \frac{1000g}{18g/mol}=55$ mol
$\rho_{H_2O} = \frac{1000g}{L}=$
$C_{H_2O}=\frac{n}{V}=\frac{55}{1}=55$ mol/liter
Smallest amount determines limiting reactant
Limitic reactant
Formation of NaCl
70 g $Na$ (s) = $n = \frac{m}{M} = \frac{70}{23} ≈ 3$ mol
70 g $Cl_2$(g) = $n = \frac{m}{M} = \frac{70}{71} ≈ 1$ → $2$ fordi 2
$2 Na + Cl_2 → 2 NaCl$