RPAL Limiting Reagents

Question 1

What is a limiting reagent in a chemical reaction?

Accepted Answer

The reactant that is completely consumed and stops the reaction

Answer

The reactant present in the largest amount

Answer

The product formed in the greatest quantity

Answer

The reagent with the highest molar mass

Question 2

In the reaction 2H₂ + O₂ → 2H₂O, if you have 4 mol H₂ and 1 mol O₂, which is the limiting reagent?

Accepted Answer

O₂

Answer

H₂

Answer

H₂O

Answer

Neither — they are in perfect ratio

Question 3

How do you identify the limiting reagent when given masses of two reactants?

Accepted Answer

Convert masses to moles, divide by coefficients, and pick the smallest result

Answer

Pick the reactant with the smaller mass

Answer

Pick the reactant with the larger molar mass

Answer

Convert masses to moles and pick the largest value

Question 4

If the limiting reagent is fully consumed, what happens to the excess reagent?

Accepted Answer

Some of it remains unreacted (leftover)

Answer

It is all converted to products

Answer

It decomposes spontaneously

Answer

It becomes the new limiting reagent

Question 5

In the reaction N₂ + 3H₂ → 2NH₃, if 1 mol N₂ and 2 mol H₂ are mixed, which is the limiting reagent?

Accepted Answer

H₂

Answer

N₂

Answer

NH₃

Answer

Both are limiting

Question 6

Which statement best describes the relationship between the limiting reagent and the theoretical yield?

Accepted Answer

The limiting reagent determines the maximum theoretical yield of product

Answer

The excess reagent determines the theoretical yield

Answer

Theoretical yield is unrelated to any single reactant

Answer

Theoretical yield depends on the product's molar mass alone