Final answer:
The most efficient ratio in the chemical equation is 2 Na: 1 Cl2. Option B) 1 mole of Na: 1 mole of Cl2 will be the most efficient set of reactants.
Step-by-step explanation:
The most efficient ratio in the chemical equation 2Na + Cl2 → 2NaCl is 2 Na: 1 Cl2. This means that for every 2 moles of sodium (Na), you need 1 mole of chlorine gas (Cl2) to produce 2 moles of sodium chloride (NaCl). Based on this ratio, the set of reactants that will be the most efficient is option B) 1 mole of Na: 1 mole of Cl2.