Question

Would you expect the reaction of propyl bromide with NaCN , which is :-

CH3CH2CH2-Br + NaCN -----> CH3CH2CH2-CN + NaBr
to occur faster in DMF or in ethanol ?explain

Answer 1

Answer:

eerrr can't figure out mate :"(

Answer 2

The reaction will occur faster in DMF.

• This is because the reaction between Propyl bromide (CH3CH2CH2-Br) and Sodium cyanide (NaCN) follows the SN2 mechanism.
• The SN2 mechanism is a single-step nucleophilic substitution reaction mechanism.
• The SN2 mechanism is promoted by polar aprotic solvents and hindered by polar protic solvents.
• DMF is a polar aprotic solvent and will favor the reaction.
• Ethanol is a polar protic solvent and will hinder the reaction.
• Polar aprotic solvents dissolve the substrate and nucleophile but they do not participate in hydrogen bonding with the nucleophile.
• Polar protic solvent will form hydrogen bonds with the nucleophile and prevent the nucleophile from binding to substrate.