3. halogenoalkanes

nucleophilic substitution (w :OH-, :CN-, :NH3) elimination reaction with :OH-

lone pair donor

nucleophile attracted to C-X bond because of it’s polarity. the C is delta +ve so nucleophile is attracted to the +ve charge

e- pair on nucleophile -> C e- pair in C-X cov bond -> X forms halide ion and product

warm aqueous produces alcohol

dissolved in ethanol (ethanolic) - if aqueous then OH- ions of water will act as nucleophile use solid kcn normally - bc gaseous hcn is difficult to maintain, and cn is toxic -hcn is a weak acid so it partially dissociates whereas kcn when dissolved fully dissociates because it’s an ionic compound.

for the process after the ammonia is added the N has whole +ve charge then another ammonia acts as a base by accepting a h+ the e- pair in cov n-h bond is donated to N hot conced ammonia in excess. bc product is a nucleophile too so to minimise further substitution —- —- formed ammonium ion and an amine

OH- ions acts as a base (proton acceptor) takes away H on the C next to the C in the CX bond. e- pair in that cov bond goes to C-C cov bond. CX cov bond goes to halogen

needs to be a H on the C next to the C in the CX bond

hot ethanolic (in these conditions OH- of NaOH acts as a base) forms alkenes, water, halide ion

adding NaOH so a ns reaction will occur, the halogen will be displaced and halide ions will form then adding acidified AgNO3 which tests for the halide ion by forming precipitates

reactivity ultimately depends on the bond strength and the polarity. increased polarity increases reactivity because ns is driven by that delta +ve charge. weaker bond strength increases reactivity because easier to break the bonds investigation showed the i.alkanes are more reactive than bromo than chloro than fluoro fluro has the most polarity but has lowest reactivity. showing that bond strength is the most significant factor in h alkanes reactivity - i alkanes have weak bonds and that’s what makes them most reactive