15 Limiting Reactant Problems: And Solutions

A limiting reactant problem is where in the stoichiometric ratio of the reactants is not given.

In this limiting reactant problems what we determine is, there is a reactant (the limiting) which limits the amount of product that can be obtained or produced.

We can solve the limiting reactant problem very easily by following the below steps:

First, write a balanced complete reaction.
The reactants should be converted to moles.
Then divide by coefficient.
The reactant obtained with a smaller number is the limiting reactant.

1. 100g of sucrose combusts with 10.0g of oxygen forming carbon dioxide and water. Which is the limiting reactant?

Solution

Step 1: Obtaining a balanced chemical equation:

C₁₂H₂₂O₁₁+ 12 O₂12 CO₂ + 11 H₂O

Step 2: Converting reactants to moles

So, in the above problem O₂ is the limiting reactant (because limiting reactant = reactant that produces least ml of product).

2. Find the limiting reactant when 4.687g of SF₄reacts with 6.281g of I₂O₅to produceIF₅ and SO₂

Solution

Step 1: Obtaining a balanced chemical equation

5SF₄ + 2I₂O₅→ 4IF₅+ 5SO₂

Step 2: Converting reactants to mole then dividing by coefficient

So, 0.0094 mol (I₂O₅) is the limiting reactant as it has the lower value as compared to SF₄ (0.00867 mol).

3. 4.5 moles of antimony reacts with 5.5 moles of oxygen according to the balanced equation, what is the limiting reactants? (Antimony →1 × 121.8 = 121.8 g/mol, oxygen (O₂) → 2 × 16.0 = 32.0g/mol)

Solution

Step 1: Obtaining a balanced chemical equation

4Sb + 30₂→ Sb₄O₆

Step 2: Already given in moles so divide by coefficient

So, Sb (1.125 mol) is the limiting reactant as it has the lower value as compared to O₂ (1.83 mol).

4. 6.7 moles of iron react with 8.4 moles of oxygen, what is the limiting reactant? (Iron →1 × 55.9 = 55.9g/mol, oxygen → 2 × 16.0 = 32.0g/mol)

Solution

Step 1: Obtaining a balanced chemical equation

4Fe + 3O₂ → 2Fe₂ O₃

Step 2: already given in moles so divide by coefficient

So, Fe (3.35 mol) is the limiting reactant as it has the lower value as compared to O₂ (5.6 mol).

5. 13 moles of phosphorus (P₄) reacts with 194 grams of water (H₂O). What is the limiting reactant? (P₄→4 x 31.0 = 124.0g/mol, H₂O→ 2 x 1.0 + 1 x 16.0 = 18.0 g/mol.

Solution

Step 1: Obtaining a balanced chemical equation

P₄ + 16H₂O →4H₃PO₄ + 10H₂

Step 2: already given in moles so divide by coefficient

So, H₂O (6.7 mol) is the limiting reactant as it has the lower value as compared to P₄ (130 mol).

6. 17 grams of bismuth (III) nitrate [Bi(NO₃)₃] reacts with 19 grams of hydrogen sulfide (H₂S) according to the balanced equation, what is the limiting reactant? (Bismuth (III) nitrate [Bi(NO₃)₃] →1 × 209.0 + 3 × 14.0 + 3 × 3 × 16.0 = 395.0g/mol)

Solution

Step 1: Obtaining a balanced Chemical equation

2Bi (NO₃)₃+ 3H₂S → BiS₃ + 6HNO₃

Step 2: Converting reactants to moles then divide y coefficient

So, O₂ (0.004 mol) is the limiting reactant as it has the lower value as compared to NH₃(0.105 mol).

7. 0.07 moles of ammonia reacts with 0.11 grams of oxygen, what is the limiting reactant? (ammonia × 1 × 4 + 3 × 1 = 17.0g/ mol, oxygen → 2 × 16 = 32g/mol )

Solution

Step 1: Obtaining a balanced chemical equation

4NH₃ + 5O₂→ 4NO + 6H₂O

Step 2: Converting reactants to moles then divide by coefficient.

So, O₂ (0.004 mol) is the limiting reactant as it has the lower value as compared to NH₃ (0.105 mol).

8. What mass in grams of aluminium hydroxide could be made from 30g Al₂S₃ and 20g H₂O, What is the limiting agent ?

Solution

Step 1: Obtaining a balanced chemical equation.

Al₂S₃+ 6H₂O → 2Al(OH)₃ + 3H₂S

Step 2: Converting reactants to moles then divide by coefficient.

So, H₂O (28.8g) is the limiting reactant as it has the lower value as compared to Al₂S₃ (31.17g).

9. What mass in grams of P₄O₆ could be made from 8.75g P₄ and 12.50g O₂ ?

Solution

Step 1: Obtaining a balanced chemical equation.

P₄ + 3O₂→ P₄O₆

Step 2: Converting reactants to moles then divide by coefficient.

So, P₄ (15.5g) is the limiting reactant as it has the lower value as compared to O₂ (28.63g).

10. What mass in grams of TiCl₄ could be made from 25g TiO₂ , 10g Carbon and 40g Cl₂ ?

Solution

Step 1: Obtaining a balanced chemical equation.

3TiO₂+ 4C + 6Cl₂ → 3TiCl₄ + 2CO₂ + 2CO

Step 2: Converting reactants to moles then divide by coefficient.

So, Cl₂ (53.5g) is the limiting reactant as it has the lower value as compared to TiO₂ (59.4g) and C (118g).

11. How many grams of water can be produced from 5.55 grams hydrogen and 4.44 grams oxygen ?

Solution

Step 1: Obtaining a balanced chemical equation.

2H₂ + O₂ → 2H₂O

Step 2: Converting reactants to moles then divide by coefficient.

So, O₂ (0.139 mol) is the limiting reactant as it has the lower value as compared to H₂ (2.75 mol).

12. If 3.22 moles of Al reacts with 4.96 moles of HBr, what will be the limiting reactant in this limiting reactant problem ?

Solution

Step 1: Obtaining a balanced chemical equation.

2Al + 6HBr → 2AlBr₃ + 3H₂

Step 2: Converting reactants to moles then divide by coefficient.

So, HBr (4.99g) is the limiting reactant as it has the lower value as compared to Al (9.737g).

13. If 21.44 moles of Si reacts with 17.62 moles of N₂, what is the limiting reactant ?

Solution

Step 1: Obtaining a balanced chemical equation.

3Si + 2N₂ → Si₃N₄

Step 2: Already in moles of so divide by coefficient.

So, Si (7.146 mol) is the limiting reactant as it has the lower value as compared to N₂ (8.81 mol).

14. Methane gas (CH₄) reacts with oxygen by combustion. How many grams of methane are needed to produce 25 grams of water?

Solution

Step 1: Obtaining a balanced chemical equation

CH₄ + 2O₂ → CO₂ + 2H₂O

Step 2: Converting reactants to moles then divide by coefficient.

Therefore 11.13g of methane is needed to produce 25 grams of water.

15. Consider the reaction NH₃ + O₂ → NO + H₂O. In an experiment 3.25 g of NH₃ are allowed to react with 3.50g of O₂. What will be the limiting reactant?

Solution

Step 1: Obtaining a balanced chemical equation

4NH₃ + 5O₂ → 4NO + 6H₂O

Step 2: Converting into moles and then dividing by coefficient.

So, O₂ (0.0219) is the limiting reactant as it has lower value as compared to NH₃ (0.0477).

16. If 75 grams of iron (III) chloride reacts with 125 grams of magnesium oxide. What will be the limiting reactant?

Solution

Step 1: Obtaining a balanced chemical equation

2FeCl₃ + 3MgO → Fe₂O₃ + 3MgCl₂

Step 2: Converting into moles and then dividing by coefficient.

So, FeCl₃ (37.267g) is the limiting reactant as it has lower value as compared to MgO (166.667g).

Also Read:

Sania Jakati

This is Sania Jakati from Goa. I am an aspiring chemist pursuing my post graduation in organic chemistry. I believe education is the key element that moulds you into a great human being both mentally and physically. I’m glad to be a member of scintillating branch of chemistry and will try my best to contribute whatever I can from my side and Lambdageeks is the best platform where I can share as well as gain knowledge at the same time.

We can solve the limiting reactant problem very easily by following the below steps:

1. 100g of sucrose combusts with 10.0g of oxygen forming carbon dioxide and water. Which is the limiting reactant?

2. Find the limiting reactant when 4.687g of SF4 reacts with 6.281g of I2O5 to produceIF5 and SO2

3. 4.5 moles of antimony reacts with 5.5 moles of oxygen according to the balanced equation, what is the limiting reactants? (Antimony →1 × 121.8 = 121.8 g/mol, oxygen (O2) → 2 × 16.0 = 32.0g/mol)

4. 6.7 moles of iron react with 8.4 moles of oxygen, what is the limiting reactant? (Iron →1 × 55.9 = 55.9g/mol, oxygen → 2 × 16.0 = 32.0g/mol)

5. 13 moles of phosphorus (P4) reacts with 194 grams of water (H2O). What is the limiting reactant? (P4→4 x 31.0 = 124.0g/mol, H2O→ 2 x 1.0 + 1 x 16.0 = 18.0 g/mol.

6. 17 grams of bismuth (III) nitrate [Bi(NO3)3] reacts with 19 grams of hydrogen sulfide (H2S) according to the balanced equation, what is the limiting reactant? (Bismuth (III) nitrate [Bi(NO3)3] →1 × 209.0 + 3 × 14.0 + 3 × 3 × 16.0 = 395.0g/mol)

7. 0.07 moles of ammonia reacts with 0.11 grams of oxygen, what is the limiting reactant? (ammonia × 1 × 4 + 3 × 1 = 17.0g/ mol, oxygen → 2 × 16 = 32g/mol )

8. What mass in grams of aluminium hydroxide could be made from 30g Al2S3 and 20g H2O, What is the limiting agent ?

9. What mass in grams of P4O6 could be made from 8.75g P4 and 12.50g O2 ?

10. What mass in grams of TiCl4 could be made from 25g TiO2 , 10g Carbon and 40g Cl2 ?

11. How many grams of water can be produced from 5.55 grams hydrogen and 4.44 grams oxygen ?

12. If 3.22 moles of Al reacts with 4.96 moles of HBr, what will be the limiting reactant in this limiting reactant problem ?

13. If 21.44 moles of Si reacts with 17.62 moles of N2, what is the limiting reactant ?

14. Methane gas (CH4) reacts with oxygen by combustion. How many grams of methane are needed to produce 25 grams of water?

15. Consider the reaction NH3 + O2 → NO + H2O. In an experiment 3.25 g of NH3 are allowed to react with 3.50g of O2. What will be the limiting reactant?

16. If 75 grams of iron (III) chloride reacts with 125 grams of magnesium oxide. What will be the limiting reactant?

2. Find the limiting reactant when 4.687g of SF₄reacts with 6.281g of I₂O₅to produceIF₅ and SO₂

3. 4.5 moles of antimony reacts with 5.5 moles of oxygen according to the balanced equation, what is the limiting reactants? (Antimony →1 × 121.8 = 121.8 g/mol, oxygen (O₂) → 2 × 16.0 = 32.0g/mol)

5. 13 moles of phosphorus (P₄) reacts with 194 grams of water (H₂O). What is the limiting reactant? (P₄→4 x 31.0 = 124.0g/mol, H₂O→ 2 x 1.0 + 1 x 16.0 = 18.0 g/mol.

6. 17 grams of bismuth (III) nitrate [Bi(NO₃)₃] reacts with 19 grams of hydrogen sulfide (H₂S) according to the balanced equation, what is the limiting reactant? (Bismuth (III) nitrate [Bi(NO₃)₃] →1 × 209.0 + 3 × 14.0 + 3 × 3 × 16.0 = 395.0g/mol)

8. What mass in grams of aluminium hydroxide could be made from 30g Al₂S₃ and 20g H₂O, What is the limiting agent ?

9. What mass in grams of P₄O₆ could be made from 8.75g P₄ and 12.50g O₂ ?

10. What mass in grams of TiCl₄ could be made from 25g TiO₂ , 10g Carbon and 40g Cl₂ ?

13. If 21.44 moles of Si reacts with 17.62 moles of N₂, what is the limiting reactant ?

14. Methane gas (CH₄) reacts with oxygen by combustion. How many grams of methane are needed to produce 25 grams of water?

15. Consider the reaction NH₃ + O₂ → NO + H₂O. In an experiment 3.25 g of NH₃ are allowed to react with 3.50g of O₂. What will be the limiting reactant?