The carbon-halogen bond breaks heterolytically, and the halogen departs as a halide ion ( X−X raised to the negative power 2. Key Nucleophilic Substitution Reactions
This reaction is highly valued in synthesis because it extends the carbon chain by one carbon atom. Equation: reactions of halogenoalkanes 1 chemsheets answers exclusive
When you change the conditions, you change the mechanism. If you use instead of aqueous, the OH−cap O cap H raised to the negative power ion acts as a base rather than a nucleophile. Reagent: KOHcap K cap O cap H dissolved in ethanol. Conditions: High temperature/Reflux. Product: Alkene + Water + Halide salt. Mechanism: The OH−cap O cap H raised to the negative power removes a proton ( H+cap H raised to the positive power If you use instead of aqueous, the OH−cap
KOH(eth)cap K cap O cap H sub open paren e t h close paren end-sub ) →right arrow Favors (Forms an Alkene) 4. Understanding SN1cap S sub cap N 1 SN2cap S sub cap N 2 Mechanisms Product: Alkene + Water + Halide salt
While fluorine is the most electronegative halogen, fluoroalkanes are the least reactive. This is because reactivity is dictated more by bond enthalpy (strength) than polarity:
In a nucleophilic substitution reaction, a nucleophile replaces the halogen atom on the alkane. On Chemsheets tasks, you are frequently asked to draw these mechanisms. Always remember to start your curly arrows from a or a negative charge. A. Reaction with Aqueous Alkali (Formation of Alcohols)