alcohols and haloalkanes

Question 1

whys the organic product more likely to be an aldehyde if distillation used

Answer 1

volatile components can escape.(alcohol) is most volatile partial oxidation occurs

Question 2

whys the organic product more likely to be a carboxylic acid if reflux is used

Answer 2

volatile components cant escape so complete oxidation will be achieved

Question 3

low volatility mean

Answer 3

it has a high bp so cant vaporise easily

Question 4

why are scientists still concerned about the ozone

Answer 4

as CFCS are still being used and they take a long time to reach the ozone layer. they remain in the atmosphere for a long time and dont readily break

Question 5

why does CF2Cl2 not hydrolyse in water

Answer 5

as the bonds need a large amount of energy to break.

Question 6

why is holes in the ozone dangerous

Answer 6

as more uv radiation will enter which can increase the risk of skin cancer.

Question 7

reactivity of haloalkanes and temp

Answer 7

chloroalkanes react the slowest iodoalkanes react the fastest as the c-I bond hydrolyses quicker than the c-br bond. Tertiary/more branched hydrolyse quicker than primary. Temp increases the rate increses as particles have more energy.

Question 8

why are CFCS useful propellants

Answer 8

as they are non toxic non flammable volatile. In fire extinguishes theyre non flammable and in areosols theyre unreactive.

Question 9

practical on hydrolysis

Answer 9

i>br>cl as the c-i bond is the weakest so hydrolyses the quickest. Ag+ +x-=AgX. add silver nitrate and ethanol to water bath the temp should be 40-80 degrees see how quickly the precipitate forms.

Question 10

practical haloalkane from an alcohol

Answer 10

round-bottom/pear shaped flask
● heat source
● condenser
Detail: water flow in condenser bottom to top; open system.Use of a heating mantel rather than a naked flame to avoid exposing flammable vapours
to a naked flame in the event of a leak
Purification
● Use of a separating funnel to separate
● organic and aqueous layers
Detail: Collect lower organic layer density greater
Drying with an anhydrous salt,
Detail: e.g. MgSO4, CaCl2, etc.
Redistillation
Detail: Collect fraction distilling at 102ºC

Question 11

whats an alternative to cfcs

Answer 11

hfcs

Question 12

oxidation for aldehyde and carboxylic acid

Answer 12

aldehyde
add acidified potassium dichromate which goes from orange to green . use heat and distillation to produce aldehyde
carboxylic
acid and potassium dichromate heat under reflux to make carboxylic acid.
distillation condensor has water flow and organic product collects in flask product is separated to prevent further oxidation.

Question 13

ozone making

Answer 13

o2(uv)=o+o=o2+o=o3

rate of formation of ozone is the same as rate of decomposition

Question 14

CF2Cl2 reacting with ozone

Answer 14

CF2Cl2(uv)=CF2Cl+cl.

cl. +o3=.clo+o2
clo. +o=o2+cl.

overall=o3+o.=2o2