Haloalkane Flashcards
1
Q
Reactivity of primary-tertiary haloalkane
A
- C-X bond in tertiary is weakest
- tertiary is most reactive
2
Q
Nucleophile
A
- ion or molecule
- electron pair donor
- forms new covalent bond
3
Q
Haloalkane to alcohol
A
Reagent: NaOH(aq)
Conditions: H2O, heat, reflux
Mechanism: nucleophilic substitution
Side product: hydrogen halide
4
Q
Halogen test
A
- Add NaOH(aq)
- neutralise with HNO3
- Add AgNO3
- precipitate is added
5
Q
AgCl (s)
A
white ppt
6
Q
AgBr
A
cream ppt
7
Q
AgI
A
yellow ppt
8
Q
Haloalkane rates test
A
- Add H20 and AgNO3(aq)
- heat in water bath 60°C
- add ethanol
- monitor rate of precipitate appearing
9
Q
Bond strength of C-X bonds
A
- bond enthalpy decreases down the group
- less energy to overcome
- reacts fastest
- quickest rate of hydrolysis
10
Q
Mechanism of chlorine radicals
A
CF2Cl2 → CF2Cl* + *Cl
*Cl + O3 → *ClO + O2
*ClO + O → *Cl + O2
11
Q
Disadvantage of chlorofluorocarbons
A
- form chlorine radicals
- reacts with ozone
- decreases absorption of UV from sun
- increased global warming
12
Q
Advantage of HCFC
A
- less stable
- more likely to break down before reaching ozone
13
Q
Use of CFC
A
- air conditioning
- refrigeration
- aerosols
14
Q
CFC benefits
A
- liquid
- readily evaporated
- non-flammable
- unreactive
- non-toxic
15
Q
Mechanism of NO radicals
A
*NO + O3 → *NO2 + O2
*NO2 + O → *NO + O2