4.2.2 - haloalkanes

Question 1

why are haloalkanes polar?

Answer 1

carbon-halogen bon is polar as halogens are more electronegative than carbon, so withdraws electron density from the carbon-halogen bond

Question 2

what is a primary haloalkane?

Answer 2

the halogen is attached to a carbon that is attached to 1 other alkyl group

Question 3

what is a secondary haloalkane?

Answer 3

the halogen is attached to a carbon that is attached to 2 other alkyl groups

Question 4

what is a tertiary haloalkane?

Answer 4

the halogen is attached to a carbon that is attached to 3 other alkyl groups

Question 5

what is a nucleophile? nucleophiles are said to be an area of ___________?

Answer 5

an electron pair donor.
a region of high electron density.

Question 6

in a mechanism what to curly arrows represent?

Answer 6

movement of a pair of electrons

Question 7

what reagents/conditions are needed for alkaline hydrolysis?

Answer 7

warm aqueous KOH or NaOH

Question 8

what type of mechanism is alkali hydrolysis?

Answer 8

nucleophilic substitution

Question 9

describe the trend in C-X bond enthalpy down group 7.

Answer 9

bond enthalpy decreases

Question 10

describe and explain the rate of alkaline hydrolysis of a haloalkane down group 7.

Answer 10

rate increases down group
this is because C-X bond enthalpy decreases

Question 11

briefly describe an experiment to compare the rates of hydrolysis of different haloalkanes.

Answer 11

carry reaction out in conical flask on top of a black cross.
add silver nitrate to the reaction mixture.
silver ions react with the halogen ions when they form, forming a precipitate.
can compare the amount of time taken for the different reactions to obscure the black cross.
down the halogen group, time for cross to be obscured decreases, because rate of hydrolysis increases.