Question

Question:Consider the equation $3A+B\to C+D.$You react 4 moles of A with 2 moles of B. Which of thefollowing is true?
a. The limiting reactant is the one with the higher molar mass.
b. A is the limiting reactant because you need 6 moles of A and have 4 moles.
C. B is the limiting reactant because you have fewer moles of B than A.
d. B is the limiting reactant because three A molecules react with each B molecule.
e. Neither reactant is limiting.
Justify your choice. For those you did not choose, explain why they are incorrect.

Short answer

Answer

A is the limiting reactant because you need 6 moles of A and have 4 moles is true. Option B is true.

Step-by-step solution

Mole ratio of A to B for the balanced equation

The given equation can be denoted as,

$3A+B\to C+D.$

Initial moles of A and B are 4 and 2 moles. The mole ratio of A to B by balanced reaction can be denoted as,

$\frac{mol A}{mol B}=\frac{3 mol A}{1 mol B}$

Mole ratio of A to B can be denoted as,

$\frac{mol A}{mol B}=\frac{4 mol A}{2 mol B}$

There are 6 moles of A need to react with B of 2 moles. The actual moles of A is 4 moles. This is the limiting reactant.

The limiting reactant is the one with the higher molar mass

There are 3 moles of A to react with 1 mole of B. But here only 2 and 1 moles of A and B. A is the limiting reactant. The moles of A greater than B. The A’s molar mass greater than B. This is incorrect.

A is the limiting reactant because you need 6 moles of A and have 4 moles

There are 3 moles of A and one mole of B, 6 moles of A can react with B. There are 4 moles of A. Here, A is the limiting reactant. This is correct.

B is the limiting reactant because you have fewer moles of B than A

There are 3 molecules which reach with B molecule. The actual moles of 1 mole is 2 mol A. B is not a molecule and it isincorrect

Neither reactant is limiting

A is the limiting reactant and it is incorrect.