Answer:
1 mol of K
Explanation:
The reaction is: 2K + Cl₂ → 2KCl
2 moles of potassium react with 1 mol of chlorine to make the salt, potassium chloride
If you see the stoichiometry from reactants, 2 moles of K need 1 mol of Cl₂ to react, so 1 mol of Cl₂ needs 2 moles of K, to react too.
We can make a rule of three, to reach the answer:
1 mol of Cl₂ needs 2 moles of K to react
Then, 0.5 moles of Cl₂ must react with (0.5 . 2) / 1 = 1 mol of K
