Chapter 4: Analyzing Organic Reactions

Question 1

What are lewis acids

Answer 1

electron acceptors; vacant orbitals or positively polarized

Question 2

What are lewis bases

Answer 2

electron donators; lone pair/anions

Question 3

what are bronsted lowry acids

Answer 3

proton donators

Question 4

what are bronsted lowry bases

Answer 4

proton acceptors

Question 5

what are amphoteric molecules

Answer 5

act as both bases/acids

Question 6

what is Ka

Answer 6

acid dissociation constant; measure of acidity; HA –> H+ + A-

Question 7

what is pKa

Answer 7

-log(Ka) ; lower pKa = stronger acid

Question 8

what is the trend of pKa on the periodic table

Answer 8

decreases down the periodic table and decreases with an increase of electronegativity

Question 9

what are alpha hydrogens

Answer 9

hydrogens connected to the alpha carbon; acidic

Question 10

what are common basic functional groups

Answer 10

amines and amides

Question 11

what are common acidic functional groups

Answer 11

alcohols, ketones, carboxylic acids, aldehydes

Question 12

what are nucleophiles

Answer 12

contain lone pairs or pi bonds; increased electron density; often carry a negative charge

Question 13

difference between nucleophilicity and basicity

Answer 13

nucleophilicity = kinetic
basicity = thermodynamic

Question 14

what affects nucleophilicity

Answer 14

charge, electronegativity, steric hinderance, solvent

Question 15

what are electrophiles

Answer 15

contain a positive charge/positively polarized; more positive = more electrophilic

Question 16

what are leaving groups

Answer 16

molecular fragments that retain the electrons after heterolysis

Question 17

what makes a good LG

Answer 17

resonance stabilization/induction; weak bases

Question 18

what is an Sn1 reaction

Answer 18

1) LG leaves forming carbocation
2) Nucleophile attacks carbocation from either side forming racemic mixture

Question 19

What makes for a good Sn1 reaction

Answer 19

more substituted carbons because alkyl groups donate electron density to stabilize carbocation

Question 20

What determines the rate of Sn1

Answer 20

concentration of substrate

Question 21

what is an Sn2 reaction

Answer 21

Nucleophile attacks at the SAME time LG leaves

Question 22

what is specific about an Sn2 reaction

Answer 22

Backside attack = inversion of stereochemistry

Question 23

what makes for a good Sn2 reaction

Answer 23

less substituted carbons for less steric hinderance for the backside attack

Question 24

what is the rate of Sn2 reaction depended on

Answer 24

concentration of substrate and nucleophile

Question 25

what is oxidation

Answer 25

increase in oxidation state ; assisted by oxidizing agents

Question 26

what are oxidizing agents

Answer 26

accept electrons and reduced in the process; high affinity for electrons

Question 27

primary alcohol –> aldehyde

Answer 27

PCC

Question 28

primary alcohol –> carboxylic acid

Answer 28

CrO3 ; Na2Cr2O7 ; K2Cr2O7

Question 29

secondary alcohol –> ketone

Answer 29

any oxidizing agent

Question 30

what is reduction

Answer 30

decrease in oxidation state ; assisted by reducing agents

Question 31

what are reducing agents

Answer 31

donate electrons and oxidized in the process

Question 32

aldehydes, ketones, carboxylic acids –> alcohol

Answer 32

LiAlH4

Question 33

amides –> amines

Answer 33

LiAlH4

Question 34

esters –> diols/pair of alcohols

Answer 34

LiAlH4

Question 35

how do you protect aldehydes and ketones

Answer 35

diols

Question 36

how do you protect alcohols

Answer 36

conversion to tert-butyl ethers