Question

Which (if any) of the following is (are) true regarding the limiting reactant in a chemical reaction? a. The limiting reactant has the lowest coefficient in a balanced equation. b. The limiting reactant is the reactant for which you have the fewest number of moles. c. The limiting reactant has the lowest ratio of moles available/coefficient in the balanced equation. d. The limiting reactant has the lowest ratio of coefficient in the balanced equation/moles available. Justify your choice. For those you did not choose, explain why they are incorrect.

Short answer

Statement c is true regarding the limiting reactant in a chemical reaction. The limiting reactant has the lowest ratio of moles available/coefficient in the balanced equation. This method accounts for both the stoichiometry of the reaction and the initial amounts of each reactant, allowing for the accurate determination of the reactant that gets depleted first and thus is the limiting reactant. The other statements (a, b, d) are either false or not always true, as they do not consider all factors necessary for identifying the limiting reactant.

Step-by-step solution

Statement a: The limiting reactant has the lowest coefficient in a balanced equation.

This statement is False. The coefficients in a balanced equation represent the stoichiometric ratio between reactants and products, not the amount of each reactant available. Therefore, the limiting reactant cannot be determined solely based on the coefficients of the reactants in the balanced equation.

Statement b: The limiting reactant is the reactant for which you have the fewest number of moles.

This statement is True sometimes, but not always. While having fewer moles of one reactant may lead it to be the limiting reactant, it is essential to consider the stoichiometric ratio of the reactants in the balanced equation. A better way of determining the limiting reactant is by dividing the moles available by the stoichiometric coefficients (as in statement c or d).

Statement c: The limiting reactant has the lowest ratio of moles available/coefficient in the balanced equation.

This statement is True. To find the limiting reactant, we must compare the initial amounts of each reactant, considering the stoichiometry in the balanced equation. Dividing the moles available of each reactant by the corresponding coefficients in the balanced equation will help us identify the reactant that gets depleted first, which is the limiting reactant. The limiting reactant will have the lowest ratio of moles available/coefficient in the balanced equation.

Statement d: The limiting reactant has the lowest ratio of coefficient in the balanced equation/moles available.

This statement is False. The limiting reactant is determined by considering the ratio of moles available/coefficient in the balanced equation, as seen in statement c, not the inverse. The inverse ratio (coefficient in the balanced equation/moles available) does not provide useful information to identify the limiting reactant. In conclusion, statement c is the only true statement of the four given options.