Limiting Reactant
- 2. Prof. Sohaib Hasnain Punjab Group of Colleges, Faisalabad CHEMISTRY
- 4. A Reactant Which Is Used Or Consumed Earlier Due To Its Lesser Amount And Controls The Amount Of Product Formed In A Chemical Reaction
- 5. Limiting Reactant It Controls the amount of product formed It is taken in lesser amount It is consumed earlier It produces least amount of product
- 6. GENERAL EXAMPLE Suppose, A and B are the reactant which react to from C. We assume that “B” is limiting reactant so, it will control the amount or “C” due to its lesser amount and it will consume earlier and reaction will not proceed further. A + B → C In this reaction, the reaction is present in large amount is called non-limiting reactant. Reactant “A” is non-limiting reactant
- 7. EXAPLES OF LIMITING REACTANT RELTAED TO CHEMICAL REACTIONS
- 8. EXAMPLE No 01 If 2 mole of H2 and 2 moles of O2 are allowed to react then 2 mole of H2O is produced 2H2 + O2 → 2H2O 4g 32g 36g In this reaction, H2 consumes completely and only one mole of O2 is consumed. One mole or Oxygen is left according to balanced chemical equation. Hence, H2 is limiting reactant and O2 is non-limiting reactant
- 9. EXAMPLE No 02 If 1 mole of C and 2 moles of O2 are allowed to react then 1 mole of CO2 is produced C + O2 → CO2 12g 32g 44g In this reaction, C consumes completely and only one mole of O2 is consumed. One mole or Oxygen is left according to balanced chemical equation. Hence, C is limiting reactant and O2 is non-limiting reactant
- 10. EXAMPLE No 03 Combustion reaction is best example to understand the concept of limiting reactant. Combustion takes place in presence of oxygen. Coal + O2 → H2O + CO2 In this reaction, coal, paper or wax which is combustible material will consume earlier due to its lesser amount and it is called limiting reactant. While the oxygen is non limiting because is present in excess amount
- 11. EXAMPLE No 04 If we have 30 “kababs” and ive breads “having 58 slices”, then we can only prepare 29 “sandwiches”. One “kabab” will be extra (excess reactant) and “slices” will be the limiting reactant. It is a practical problem that we can not purchase exactly sixty “slices” for 30 “kababs” to prepare 30 “sandwiches”
- 13. THREE STEP SHOULD BE FOLLOWED TO FIND OUT THE LIMITING REACTANT i. Calculate the number of moles from given amount of reactant ii. Find out the number of moles or product with the help of balanced chemical equation iii. Identify the reactant which produces the least amount as limiting reactant
- 14. CONCEPT OF LIMITING REACTANT IS NOT APPLICABLE ON THE REVERSIBLE REACTION
- 15. JUSTIFICATION “A Reactant Which Is Used Or Consumed Earlier Due To Its Lesser Amount And Controls The Amount Of Product Formed In A Chemical Reaction” During a reversible reaction, reactants are converted into product and products convert back into reactant. So reactants are not completely consumed. As a result a limiting reactant cannot be identified in reversible reaction