The reaction involves adding Na and Cl₂ gas to form NaCl
since chlorine is a halogen it exists as a diatomic molecule - Cl₂
the balanced equation is
2Na + Cl₂ --> 2NaCl
the molar ratio reactants Na to Cl₂ is 2:1
the mass of Na present is 35.0 g
therefore number of moles of Na is - 35.0 g / 23 g/mol = 1.52 mol
according to the molar ratio , the number of Cl₂ moles required is half the number of Na moles present
If 2 moles of Na reacts with 1 mol of Cl₂
then 1.52 mol of Na reacts with - 1/2 x 1.52 mol = 0.760 mol of Cl₂
molar mass of Cl₂ is - 71.0 g/mol
number of Cl₂ moles are - 0.760 mol x 71.0 g/mol = 54.0 g
answer is 54.0 g of Cl₂ is needed
