The balanced equation for the reaction of nitrogen gas and fluorine gas is

N2(g) + 3 F2(g) → 2 NF3(g)

What is the limiting reactant if 25 N2 molecules are allowed to react with 75 F2 molecules?

a. N2
b. F2
c. NF3
d. There is no limiting reactant: the reactants are present in stoichiometrically equivalent amounts
e. More information is needed to solve this problem

We don't have a limiting reactant.

The reactants are present in stoichiometrically equivalent amounts.

Option D is correct

Explanation:

Step 1: Data given

Molecules N2 = 25 molecules

Molecules F2 = 75 molecules

Number of Avogadro = 6.02 * 10^23 / moles

Step 2: Calculate moles N2

Moles N2 = molecules N2 / number of Avogadro

Moles N2 = 25 / 6.02 * 10^23

Moles N2 = 4.15 * 10^-23 moles

Step 3: Calculate moles F2

Moles F2 = 75 molecules / 6.02 * 10^23

Moles F2 = 1.25 *10^-22 moles

Step 4: Calculate limiting reactant

For 1 mol N2 we need 3 moles F2 to produce 2 moles NF3

For 4.15 * 10^-23 moles N2 we need 1.25 * 10^-22 moles F2

OR  

For 25 molecules N2 we need 75 molecules F2

Both reactants will completely react.

This means we don't have a limiting reactant.

The reactants are present in stoichiometrically equivalent amounts.

Option D is correct