Final answer:
The limiting reactant is Cl2 since 4.00 mol of Sb would need 6.00 mol of Cl2 to fully react according to the stoichiometry of the balanced equation, and only 5.00 mol of Cl2 is available.
Step-by-step explanation:
To determine the limiting reactant when 4.00 mol of Sb are reacted with 5.00 mol Cl according to the equation: 2 Sb + 3 Cl2 = 2 SbCl3, we begin by calculating the mole ratio as given by the balanced equation.
Firstly, using the balanced equation, we can see that 2 moles of Sb require 3 moles of Cl2 for complete reaction. This means that each mole of Sb requires 1.5 moles of Cl2. Therefore, to react with 4.00 mol of Sb, we would need 6.00 mol of Cl2. However, we only have 5.00 mol of Cl2, indicating that Cl2 is the limiting reactant as it will be entirely consumed first before Sb runs out.
Note that the stoichiometric coefficient for Cl is 3, indicating that Cl2 is diatomic and must be counted as such when considering reaction stoichiometry.