Halogenoalkanes 1/3

These flashcards cover key concepts related to halogenoalkanes, their properties, naming conventions, and reactions.

What are halogenoalkanes?

Alkanes with one or more halogens attached to them.

What is the first step in naming a halogenoalkane?

Find the longest carbon chain.

What is the second step of naming Halogenoalkanes

The names and position of the halogen on the molecule is the prefix

How are the names of halogens in halogenoalkane naming ordered?

They must be in alphabetical order.

What prefixes are used for multiple types of halogens in names?

Use 'di' for 2, 'tri' for 3, and 'tetra' for 4.

How do boiling points of halogenoalkanes change down the group?

Boiling points increase down the group.

What factors govern the boiling point of halogenoalkanes?

The strength of the intermolecular forces.

Why do the boiling points down group 7 have that trend

As you descend down group 7 the number of electrons in the hydrogen atoms increases, and more electrons means stronger van der waals forced between the molecules and so more energy is needed to overcome these forces

Why do halogenoalkanes have polar bonds?

Halogens are more electronegative than carbon and pull electrons towards themselves,

What does having polar bonds do to the Halogenoalkanes

They are attacked by nucleophiles

What is a nucleophile?

A substance that is an electron pair donor.

Give examples of nucleophiles.

Ammonia, hydroxide ions, cyanide ions

What mechanism is the reaction for hydroxide ions and Halogenoalkanes

Nucleophilic substitution

What are the conditions of nucleophilic substitution

Warm aqueous sodium hydroxide, which is the source of the OH- ions, and carried out under REFLUX

What happens during a nucleophilic substitution with hydroxide ions?

A nucleophile attacks the carbon and replaces the halogen, meaning that a new bond is formed between the OH- ion and the carbon

What is formed when halogenoalkanes react with cyanide ions?

Nitriles are formed.

What is formed in the nucleophilic substitution of hydroxide ions and a Halogenoalkane

Alcohol

What happens during a nucleophilic substitution with cyanide ions?

A nucleophilic with attack the slightly positive carbon and will replace the halogen, meaning that a new bond is formed between the CN- ion and the carbon

What conditions are required for nucleophilic substitution with cyanide ions?

Warm ethanolic potassium cyanide and carried out under reflux.

What is the overall reaction of halogenoalkanes with sodium hydroxide?

R-X + NaOH → ROH + NaX, where R is an alkyl group and X is a halogen.

What occurs to the C-X bond during nucleophilic substitution?

The C-X bond breaks, and both electrons move to the halogen.

What is the overall reaction of halogenoalkanes with ethanolic potassium cyanide

R-X + KCN → RCN+ KX, where R is an alkyl group and X is a halogen.