Halogenoalkanes - exam practice

electron pair donors that attack regions of high electron density

electron pair donors that attack regions of low electron density

electron pair acceptors that attack regions of high electron density

electron pair acceptors that attack regions of low electron density

(CH₃)₂CHCH₂Cl reacts with NaOH_(aq) by an S_N2 mechanism

the tertiary chloroalkane reacts more quickly than the others because the carbon atom bonded to the Cl atom is more positive in this molecule

the Cl atoms in the three chloroalkanes are attacked by OH^-

the molecular formula of the major product is C₄H₈ for each reaction

1

2

3

4

CH₃CH₂CHClCH₃

(CH₃)₂CClCH₃

CH₂ClCH₂CH₂CH₃

CH₂ClCH₂CH₂CH₂Cl

electrophilic addition

nucleophilic addition

free radical substitution

nucleophilic substitution

attack by a nucleophile on a carbon atom with a partial positive charge

heterolytic bond fission followed by attack by an electrophile on a carbanion

heterolytic bond fission followed by attack by a nucleophile on a carbocation

homolytic bond fission followed by attack by a nucleophile on a carbocation

•CH₂Cl

•CH₂Br

•CHBrCl

•CH₂BrCl

homolytic fission

heterolytic fission

an initiation reaction

a propagation reaction

NH₃ attacks the halogen atom

NH₂^- attacks the carbon atom next to the halogen

NH₃ forms a bond with its lone pair to the carbon atom next to the halogen

the halogen atom is lost as a radical

fluoroethane has the higher boiling point because it forms hydrogen bonds

fluoroethane has the higher boiling point because the C-F bond is stronger than C–I

iodoethane has the higher boiling point because it forms the stronger instantaneous dipole–induced dipole bonds

iodoethane has the higher boiling point because the C-I bond is less polar than C-F

the C-I bond enthalpy is greater than the C-Cl bond enthalpy

the C-I bond is less polar than the C-Cl bond

the C-I bond has a C atom with a greater δ⁺ charge than in the C-Cl bond

the C-I bond requires less energy to break than the C-Cl bond

1 > 2 > 3

3 > 2 > 1

2 > 1 > 3

3 > 1 > 2

1

2

3

4

it attacks a double bond

it donates a lone pair of electrons

it is a single atom

it is negatively charged

(C₂H₅)₂NH₂⁺Cl^-

C₂H₅NH₄⁺Cl^-

NH₂CH₂COCl

C₂H₅NHCOC₂H₅