SN1 and SN2

• How do SN1 and SN2 reactions differ in their mechanisms?

  SN1 is two-step; SN2 is one-step
• What forms during an SN1 reaction?

  Carbocation
• What happens to chirality in SN1 reactions?


  Loss of chirality occurs
• What is the configuration change in SN2 reactions?

  Inversion of configuration
• What are the steps in an SN1 reaction?

  1. Leaving group departs to form a carbocation
  2. Nucleophile attacks the carbocation
• What is the nature of the attack in an SN2 reaction?

  Backside attack
• How does the timing of steps differ between SN1 and SN2 reactions?


  SN1 has two steps; SN2 has one step
• What type of substrate favors SN1 reactions?

  Tertiary substrates
• What is the stability order of carbocations in SN1 reactions?

  Tertiary > Secondary > Primary
• What stabilizes tertiary carbocations in SN1 reactions?

  Hyperconjugation
• Which alkyl halide undergoes SN1 more readily: (CH₃)₃CBr or CH₃CH₂Br?


  (CH₃)₃CBr
• What type of substrate is required for SN2 reactions?

  Primary substrates
• How does steric hindrance affect SN2 reaction rates?


  Higher steric hindrance slows reactions
• Which alkyl halide reacts quickly via SN2: CH₃Br or (CH₃)₃CBr?


  CH₃Br
• What is the role of a nucleophile in SN1 reactions?

  Attacks the carbocation
• What type of nucleophile favors SN2 reactions?

  Strong nucleophiles
• What type of nucleophile favors SN1 reactions?

  Weak nucleophiles
• What is a good leaving group in SN1 and SN2 reactions?

  Halides
• What is the preferred nucleophile in the reaction of CH₃Br with OH⁻?


  OH⁻
• What is the difference in stereochemistry between SN1 and SN2 reactions?

  SN1 racemizes; SN2 inverts
• What is the substrate preference order for SN2 reactions?

  Primary > Secondary > Tertiary
• What type of nucleophile is favored in SN1 reactions?

  Weak nucleophiles
• What type of nucleophile is favored in SN2 reactions?

  Strong nucleophiles
• What is the difference in reaction steps between SN1 and SN2?


  SN1 has two steps; SN2 has one step
• What is the effect of steric hindrance on SN2 reactions?


  Increased steric hindrance slows reactions
• What is the preferred substrate for SN2 reactions?

  Primary substrates
• What is the role of a leaving group in SN1 reactions?

  Departs to form the carbocation
• What is the role of a leaving group in SN2 reactions?

  Departs simultaneously with nucleophile attack
• What is the effect of nucleophile strength on SN1 and SN2 reactions?


  Weak nucleophiles favor SN1; strong favor SN2
• What is the preferred substrate for SN1 reactions?

  Tertiary substrates
• What type of nucleophiles does the SN1 mechanism favor?

  Weaker nucleophiles like alcohols
• Why do weaker nucleophiles favor the SN1 mechanism?

  They prefer reactions with carbocation intermediates
• What are examples of weak nucleophiles?

  Alcohols, water, carboxylic acids
• What characterizes strong nucleophiles in SN2 reactions?

  They are highly electron-rich and negatively charged
• What are examples of strong nucleophiles?

  Cyanide, azide, thiolate, hydroxide
• What are the key differences between SN1 and SN2 reaction mechanisms?

  • SN1: Two-step mechanism, carbocation intermediate, racemization
  • SN2: Single-step mechanism, direct backside attack, inversion
• What is the stereochemical outcome of an SN1 reaction?

  Racemization of products
• What happens to stereochemistry in an SN2 reaction?

  It results in inversion of configuration
• How does the transition state differ between SN1 and SN2 reactions?

  SN1 has a carbocation, SN2 has a single transition state
• What is the activation energy in a reaction?

  The energy barrier to reach the transition state