Question

Hydrogen reacts with sodium to produce solid sodium hydride. A reaction mixture contains 6.75 g Na and 3.03 g Hydrogen. Which reactant is limiting?

Answer 1

Na

Step-by-step explanation:

To find the limiting reactant we must first write the balanced chemical reaction. It must be correctly balanced so that we can find the proper mole ratios.

2 Na + H₂ → 2 NaH

After this we will convert our measurements to moles. For mass we do this by dividing by the molar mass.

6.75g ÷ 22.99 = 0.294mol Na

3.03g ÷ 2.02 = 1.50mol H₂

Now that we have the moles of each of the reactants, we can multiply them by their mole ratio with a reactant.

0.294mol Na ×
`(2 Na)/(2 NaH)` = 0.294mol NaH

1.50mol H₂ × 2/1 = 3.00mol NaH

Na is our limiting reagent because it makes the smaller amount of moles.