Haloalkanes

Question 1

What is a nucleophile?

Answer 1

Lone Pair Donor

Question 2

Why are Haloalkanes readily attacked by nucleophiles?

Answer 2

Carbon-Halogen bond is polar so that the C atom is delta plus and so is attacked by nucleophiles

Question 3

Explain why 1-iodopropane reacts faster with nucleophiles than 1-chloropropane, assuming the same reaction conditions

Answer 3

C-I bond is longer and therefore weaker than C-Cl bond

Question 4

How can we ensure a better yield of primary amine is obtained when haloalkanes react with ammonia?

Answer 4

Use an excess of ammonia to prevent further substitutions from occurring

Question 5

State whether ethane or chloroethane would have a higher boiling point. Explain your answer. (Bonding Recap)

Answer 5

•Chloroethane
•Larger molecule therefore stronger London forces between molecules

Question 6

What are CFCs?

Answer 6

•Chloro-fluoro-carbons
•Haloalkanes containing C,F and Cl only (No H)

Question 7

What is the problem with CFCs?

Answer 7

Although unreactive under normal conditions, they catalyse the breakdown of ozone in the atmosphere via free radical substitution

Question 8

What are the three most common nucleophiles?

Answer 8

CN:-
:NH3
:OH-

Question 9

What is the correlation between Mr and bond enthalpy of halogens?

Answer 9

The greater the Mr, the lower the bond enthalpy

Question 10

What are the conditions and reagent for the hydrolysis reaction with Hydroxide ions?

Answer 10

Reagent: Aqueous Sodium Hydroxide
Conditions: Warm,Aqueous

Question 11

What are the conditions and reagent for reacting haloalkanes with excess ammonia?

Answer 11

Conditions: Excess NH3
Reagent: NH3 dissolved in ethanol (ethanolic ammonia)