Question

4. Sn1 reactions are unimolecular and Sn2 reactions are bimolecular. What does this mean? Write the generic rate laws for Sn1 and Sn2 reactions. Which reagents do the rates of Sn1 and Sn2 reactions depend on? 5. Consider tert-butylchloride and 2-chloropropane. Which of these compounds is more likely to react via an Sn1 mechanism? Which is more likely to reactive via an Sn2 mechanism? Explain your answer. 6. Rank the following compounds in order of increasing likelihood of undergoing substitution reactions by an Sn2 mechanism. Br Br Br

Answer 1

• [unimolenlar ] Substrate only SNI s The SNi reaution Blates for SN means Nucleophilic substitution and I' meoms unimoleuter means the rate determining step is one modelelor. In SNI reaction polar protic Solvent is used like Alcohals Cats on the The order of SNg reactivity in the stability of Carbo caution Higher the stable Carbolation, more Blathe product will be formed. • og 3323 to Substate a f Nucleophile r Bimoleculen] SN » A nucleophic Substitution Reaction in which in Rate determining Steps 2 component enverely is called SN2 Reaction • there in SN2 Stability of product depends on Haric Hindromee lower the steric Hindremce signer the stability [13 2 3 3 ) groups ordes of siz stabity. solrent used in polar apsotic eg: Dmso, acetone Rate of (SN2) = K [Nuclophile ] [ R-2] fate of (SN) = K[R-L] Le leaving group R=Carbon grape & Nurheophice S trate Substrate

Tertiary, Butyl chloride 2-chlone propone • As we know that she reaction is very less in stevie hindered group so SN2 Not Tertiary - Butlyl chloride ress hindered. more hindered : Bare of Snax Y > Tali ... 2-chlorpropone give SN2 give SN, because And Tertiary - Butly chloride it will form 3° Carbo Contion. leaving group remoral. 2-choro propone Sois Terbong. Butyt chord SNI SN

Rank in SNa reaution By WO txplaination Ex I ) ) JIJI Cooder of Swe reactivity) Belante care of sore reaction to be als po ...( Dj . And in (II) part the Carbocmin formed in resonance stablired . Il in most stabliced anion, so I S NJI) and (I) is very less reactive because the Carbanion formed on pi-bond is highly unstable. so overall order in (1) IUSI)