R−X+OH−→R−OH+X−cap R minus cap X plus cap O cap H raised to the negative power right arrow cap R minus cap O cap H plus cap X raised to the negative power B. Reaction with Potassium Cyanide ( CN−cap C cap N raised to the negative power KCNcap K cap C cap N in ethanol/water Conditions: Reflux Nucleophile: Cyanide ion ( Product: Nitrile
: When asked to order halogenoalkanes by increasing rate of reaction with AgNO₃, the order is always CH₃Cl < CH₃Br < CH₃I, reflecting increasing C-X bond weakness.
Dissolved in ethanol (ethanolic), heated under reflux. Product: Nitrile. reactions of halogenoalkanes 1 chemsheets answers exclusive
. This is a vital reaction because it increases the carbon chain length. Conditions: Ethanol solvent, reflux. With Ammonia (NH₃): The halogen is replaced by an -NH₂ group , forming a primary amine Conditions: Excess ammonia, ethanolic, heated in a sealed tube. 2. Elimination Reactions Under different conditions, the hydroxide ion acts as a
: These reactions occur in two steps. The first step involves the formation of a carbocation intermediate, which is a slow and rate-determining step. The second step involves the attack of a nucleophile on the carbocation to form the final product. SN1 reactions are typically observed in secondary and tertiary halogenoalkanes. R−X+OH−→R−OH+X−cap R minus cap X plus cap O
: Why is excess ammonia used? This is to minimize further substitution of the primary amine product, which would otherwise react with more halogenoalkane to form secondary and tertiary amines.
Potassium cyanide (KCN) dissolved in ethanol/water mixture. The Product: Nitrile (alkanenitrile). The Mechanism: Nucleophilic substitution (typically SN2). Product: Nitrile
Concentrated ammonia solution, heated in a sealed copper tube (to withstand pressure from volatile ammonia gas). Product: Primary amine (and an ammonium salt). Equation:
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base attacks a hydrogen atom attached to a carbon adjacent to the carbon holding the halogen (the bond breaks, and its electron pair shifts to form a