Limiting reactant is a reactant on which amount of product depend upon.

1. LIMITING REAGENT

2. DEFINITION
The limiting reactant is a reactant that controls the amount of
the product formed in a chemical reaction due to its smaller
amount.
Limiting
reactant Excessive
reactant

3. EXAMPLE

4. • The concept of limiting reactant is analogous to the relationship
between the number of “kababs” and the “slices” to prepare
“sandwiches”.

5. If we have 30 “kababs”

6. and ive breads “having 58 slices”,

7. then we can only prepare 29 “sandwiches

8. One “kabab” will be extra (excess reactant)
and “slices” will be the limiting reactant.

9. It is a practical problem that we can not purchase
exactly sixty “slices” for 30 “kababs” to prepare 30
“sandwiches”.

10. EXAMPLE
• Consider the reaction between hydrogen and oxygen to form water.
2H2 (g) + O2 (g) 2H2O(l)
• When we take 2 moles of hydrogen (4g) and allow it to react with 2
moles of oxygen (64g), then we will get only 2 moles (36 g) of water.
Actually, we will get 2 moles (36g) of water because 2 moles (4g) of
hydrogen react with 1 mole (32 g) of oxygen according to the
balanced equation. Since less hydrogen is present as compared to
oxygen, so hydrogen is a limiting reactant. If we would have reacted 4
moles (8g) of hydrogen with 2 moles (64 g) of oxygen, we would have
obtained 4 moles (72 g) of water.

11. Identification of limiting reactant
• To identify a limiting reactant, the following three steps are
performed.
• 1. Calculate the number of moles from the given amount of reactant.
2. Find out the number of moles of product with the help of a
balanced chemical equation.
• 3. Identify the reactant which produces the least amount of product
as limiting reactant.

12. THANKS