# Sample problems addition, substitution and elimination reactions

1. Question: How many moles of bromine (Br₂) are required for the addition reaction with 5 moles of propene (C₃H₆)? Solution: The reaction is C₃H₆ + Br₂ → C₃H₆Br₂. From the stoichiometry, 1 mole of C₃H₆ reacts with 1 mole of Br₂. Thus, 5 moles of C₃H₆ will require 5 moles of Br₂.

2. Question: You have 8 moles of ethene (C₂H₄) and you add hydrogen (H₂) in excess. How many moles of ethane (C₂H₆) will you produce? Solution: The reaction is C₂H₄ + H₂ → C₂H₆. From the stoichiometry, 1 mole of C₂H₄ reacts with 1 mole of H₂ to give 1 mole of C₂H₆. Thus, 8 moles of C₂H₄ will give 8 moles of C₂H₆.
3. Question: How many moles of water (H₂O) are required for the substitution reaction with 7 moles of chloromethane (CH₃Cl)? Solution: The reaction is CH₃Cl + H₂O → CH₃OH + HCl. From the stoichiometry, 1 mole of CH₃Cl reacts with 1 mole of H₂O. Thus, 7 moles of CH₃Cl will require 7 moles of H₂O.
4. Question: You have 10 moles of bromoethane (C₂H₅Br) and you react it with sodium hydroxide (NaOH) in excess. How many moles of ethanol (C₂H₅OH) will you produce? Solution: The reaction is C₂H₅Br + NaOH → C₂H₅OH + NaBr. From the stoichiometry, 1 mole of C₂H₅Br reacts with 1 mole of NaOH to give 1 mole of C₂H₅OH. Thus, 10 moles of C₂H₅Br will give 10 moles of C₂H₅OH.
5. Question: How many moles of potassium tert-butoxide (KOtBu) are required for the elimination reaction with 6 moles of 2-bromopropane (C₃H₇Br)? Solution: The reaction is C₃H₇Br + KOtBu → C₃H₆ + KBr + tBuOH. From the stoichiometry, 1 mole of C₃H₇Br reacts with 1 mole of KOtBu. Thus, 6 moles of C₃H₇Br will require 6 moles of KOtBu.
6. Question: You have 15 moles of 2-chlorobutane (C₄H₉Cl) and you react it with sodium ethoxide (NaOEt) in excess. How many moles of but-2-ene (C₄H₈) will you produce? Solution: The reaction is C₄H₉Cl + NaOEt → C₄H₈ + NaCl + EtOH. From the stoichiometry, 1 mole of C₄H₉Cl reacts with 1 mole of NaOEt to give 1 mole of C₄H₈. Thus, 15 moles of C₄H₉Cl will give 15 moles of C₄H₈.
7. Question: How many moles of hydrochloric acid (HCl) are required for the substitution reaction with 9 moles of methanol (CH₃OH)? Solution: The reaction is CH₃OH + HCl → CH₃Cl + H₂O. From the stoichiometry, 1 mole of CH₃OH reacts with 1 mole of HCl. Thus, 9 moles of CH₃OH will require 9 moles of HCl.
8. Question: You have 12 moles of ethene (C₂H₄) and you add bromine (Br₂) in excess. How many moles of 1,2-dibromoethane (C₂H₄Br₂) will you produce? Solution: The reaction is C₂H₄ + Br₂ → C₂H₄Br₂. From the stoichiometry, 1 mole of C₂H₄ reacts with 1 mole of Br₂ to give 1 mole of C₂H₄Br₂. Thus, 12 moles of C₂H₄ will give 12 moles of C₂H₄Br₂.
9. Question: How many moles of potassium hydroxide (KOH) are required for the elimination reaction with 4 moles of 2-iodopropane (C₃H₇I)? Solution: The reaction is C₃H₇I + KOH → C₃H₆ + KI + H₂O. From the stoichiometry, 1 mole of C₃H₇I reacts with 1 mole of KOH. Thus, 4 moles of C₃H₇I will require 4 moles of KOH.
10. Question: You have 3 moles of 2-chloropentane (C₅H₁₁Cl) and you react it with potassium methoxide (CH₃OK) in excess. How many moles of pent-2-ene (C₅H₁₀) will you produce? Solution: The reaction is C₅H₁₁Cl + CH₃OK → C₅H₁₀ + KCl + CH₃OH. From the stoichiometry, 1 mole of C₅H₁₁Cl reacts with 1 mole of CH₃OK to give 1 mole of C₅H₁₀. Thus, 3 moles of C₅H₁₁Cl will give 3 moles of C₅H₁₀.