Haloalkanes

Question 1

C-X bond polarity nature (5)

Answer 1

Polar
Halogens more electronegative than carbon
Down group, decrease polarity
Not polar enough to dissolve in water
Mix with HCs (remove oily stains)

Question 2

Haloalkane IMFs

Answer 2

Permanent dipole
London forces

Question 3

Boiling point haloalkanes (4)

Answer 3

Longer chain length, higher boiling point
Down group, increase boiling point
Higher bp than same carbon chain length alkanes
- More electrons
- More electron density
- Stronger London forces
More branching, decrease bp

Question 4

Haloalkanes reactivity (6)

Answer 4

Down group, decrease polarity
Down group, decrease C-X bond enthalpy
Down group, increase reactivity
Bond enthalpy more important than polarity
Break C-X, hydrolyse
Increase halogen size, increase bond length, decrease bond enthalpy (easier to break)
C-F slowest
C-I fastest

Question 5

Classification

Answer 5

No. Alkyl groups bonded to C-X carbon
Primary- 1
Secondary- 2
Tertiary- 3

Question 6

Nucelophile

Answer 6

Electron pair donor
Negative ion/delta negative atom
Lone e pair (electronegative) - > cov bond
Donates es —> e deficient C atom

Question 7

Name 3 nucleophiles

Answer 7

:OH-
:NH3
:CN-
Replace halogen in haloalkane

Question 8

Heterolytic fission

Answer 8

Splitting of a covalent bond to give 1 atom both electron previously in a shared pair

Question 9

Alcohol nucleophilic substitution
Nucleophile
Reagant
Conditions

Answer 9

:OH-
KOH/NaOH
Warm, aqueous, reflux

Question 10

Alcohol primary/tertiary nucleophilic substitution difference

Answer 10

Primary, 1 step
Tertiary, 2 step, electron to X, then nucleophile bonds

Question 11

Nitrile nucleophilic substitution
Nucleophile
Reagant
Conditions

Answer 11

:CN-
KCN(aq), water/ethanol
Heat under reflux
Makes a alkanenitrile

Question 12

Amine nucleophilic substitution
Nucleophile
Reagant
Conditions

Answer 12

:NH3
Warm, excess ethanolic ammonia
Pressure
Makes a alkylamine
2 step, forms a NH3+, then a NH2 and NH4Br

Question 13

Elimination

Answer 13

Removal of small compounds (H2O/HCl)
Form a double bond
Hydrogen halide —> alkene

Question 14

Elimination using OH- ion conditions

Answer 14

Ethanolic solution (KOH/NaOH)
Reflux high temp

Question 15

Elimination using OH- ion procedure

Answer 15

OH- is a base
Accepts H+ from haloalkane adjacent to halogen
Halogen gains electrons from haloalkane
Forms water, hydrogen and an alkene

Question 16

Substitution vs elimination
Solvent, temp, product, OH- action

Answer 16

S - water, warm, alcohol, nucelophile
E - ethanol, hot, alkene, base

Question 17

Classifications, sub vs elim

Answer 17

Prim, sub
Sec, both
Tert, elim

Question 18

Hydrolysis procedure

Answer 18

Molecule broken down using water
Water is nucleophile, breaks C-X bond
Slower than KOH/NaOH

Question 19

Hydrolysis testing results

Answer 19

Add AgNO3
X- reacts AgNO3 —> ppte
Compare reactivity/rate of formation
Ammonia test
Fastest, lowest enthalpy, longest bond length, easiest to break, increase hydrolysis rate

Question 20

Hydrolysis conditions

Answer 20

Warm 50*C
Water bath
Ethanol, dissolve haloalkane and AgNO3