nucleophilic substitution reactions Flashcards
OZ7
define nucleophile
a nucleophile is a species with a lone pair of electrons, which it donates to a delta positive carbon, forming a new covalent bond.
define substitution reaction
substitution reactions are where one atom or group in a molecules gets replaced by another atom or group
define nucleophile
a nucleophile is a species with a lone pair of electrons, which it donates to a delta positive carbon forming a new covalent bond
define substitution reaction
substitution reactions are when one atom or group in a molecule gets replaces by another atom or group
name the conditions and reagents needed for the reaction of an alkane and OH- ions
reagents: NaOH (aq) which provides the OH- ions (Na+ are spectator ions)
conditions: heat under reflux
what is reflux?
Reflux is where a liquid reaction mixture is boiled in a flask connected to a vertical condenser. this is used when the mixture needs heating for a while as it prevents loss of reactants and products as vapour, the compounds continuously evaporate then condense and drip back down into the mixture.
describe an alkanes reaction with water
water can act as a nucleophile as the oxygen has a lone pair that it can donate and is delta negative. But it is a weaker nucleophile s=than OH- ions (as water does not have a full - charge) the reaction is very slow, as with OH- the product is an alcohol
how many stages are there in a reaction between an alkane and a water molecule?
Three.
there is an intermediate stage, since the O still has 2 hydrogens bonded so it needs to break the bond between the O and H before the reaction is complete
what are the reactants and conditions required for an alkane to react with ammonia (NH3)?
since ammonia is a nucleophile without a full minus charge, the reaction is vigorous.
reactants: concentrated ammonia solution
conditions: heat in a sealed tube
how many stages does a reaction between ammonia and an alkane have?
similar to water, an alkane and ammonia reacting have 3 stages. this is because there needs to be a bond broken between the N and one of the three H
what’s NH2 group called?
an amine