Halogenoalkenes

Question 1

Why does the carbon that the halogen is attached to in a halogenoalkane have a slight positive charge?

Answer 1

The halogen is more electronegative compared to the carbon means it pulls the pair of electrons in the covalent bond towards it and away from the carbon which gives the carbon that positive charge.

Question 2

What is a nucleophile?

Answer 2

an electron pair donor

Question 3

What is a substitution reaction?

Answer 3

Swapping out a halogen atom for another atom.

Question 4

What is the name of the mechanism for when a halogenoalkane is turned into an alcohol?

Answer 4

nucleophilic substitution

Question 5

What conditions are needed for this reaction?

Answer 5

1. Warm aqueous sodium or potassium hydroxide.
2. Heat under reflux

Question 6

Name and outline the mechanism for the formation of an alcohol when bromoethane reacts with potassium hydroxide.

Question 7

What is the name of the mechanism for when a halogenoalkane is turned into a nitrile?

Answer 7

nucleophilic substitution

Question 8

What conditions are needed for this reaction?

Answer 8

potassium cyanide dissolved in ethanol and water
heated under reflux

Question 9

Name and outline the mechanism for the formation of a nitrile when bromoethane reacts with potassium cyanide.

Question 10

What is the name of the mechanism for when a halogenoalkane is turned into an amine?

Answer 10

nucleophilic substitution

Question 11

What conditions are needed for this reaction?

Answer 11

An excess of ammonia dissolved in ethanol. Heated under pressure.

Question 12

Name and outline the mechanism for the formation of an amine when bromoethane reacts with excess ammonia.

Question 13

What is an elimination reaction?

Answer 13

The removal of a small molecule from an organic molecule.

Question 14

What is the name of the mechanism for when a halogenoalkane is turned into an alkene?

Answer 14

elimination

Question 15

What conditions are needed for this reaction?

Answer 15

Warm the halogenoalkane with hydroxide ions dissolved in ethanol. heated under reflux.

Question 16

Name and outline the mechanism for the formation of an alkene when bromoethane reacts with ethanolic potassium hydroxide.

Question 17

Why do fluoroalkanes undergo nucleophilic substitution much more slowly compared to chloroalkanes?

Answer 17

The carbon-fluorine bond has a higher bond enthalpy compared to a carbon-iodine bond meaning it is less easy to break and the fluorine takes more time to be released so it can be substituted.