Organic Reactions

Question 1

Lewis acid

Answer 1

An electron acceptor; electrophile

Question 2

Lewis base

Answer 2

An electron donor; nucleophile

Have a lone pair and often are carrying a negative charge.

Question 3

Bronsted-Lowry acid

Answer 3

a species that can donate a proton

Question 4

Bronsted-Lowry base

Answer 4

A species that can accept a proton

Question 5

Amphoteric

Answer 5

Can act as either Bronsted-Lowry acids, or bases i.e. water.

Whether it acts as an acid or a base depends upon the solution that it’s in – water can only act as a base in acidic solution and vice versa.

Question 6

pKa

Answer 6

= -log K_a

the smaller the pKa, the stronger the acid; acids with pKa below -2 are considered strong acids, which almost always completely dissociate in aqueous solution.

Question 7

Functional group acids

Answer 7

alcohols, aldehydes, ketones, carboxylic acids, and most carboxylic acid derivatives. (accept a lone pair)

Question 8

Functional group bases

Answer 8

Amines and amides (donate a lone pair)

Question 9

Nucleophiles`

Answer 9

Tend to have lone pairs or π bonds that can be used to form covalent bonds to electrophiles.

Nucleophilicity is determined by 4 major factors:

1. Charge
2. Electronegativity
3. Steric hindrance
4. Solvent; protonation or h-bonding by protic solvents can hinder nucleophile

Question 10

Solvent Effects

Answer 10

In polar protic solvents, nucleophilicity increases down the periodic table.

In polar aprotic solvents, nucleophilicity increases up the periodic table

Polar solvents – whether protic or aprotic – can dissolve nucleophiles and assist in any reaction in whihc electrons are moved.