LECTURE 7 (Monofunctional compounds)

Question 1

What are alcohols and phenols?

Answer 1

Compounds that have an organic group bonded to an -OH group

• Alcohols = A compound that has an -OH group bonded to a saturated, alkane-like carbon atom R-OH
• Phenols = A compound that has an -OH group bonded directly to an aromatic, benzene-like ring Ar-OH

Question 2

What are Ethers?

Answer 2

A compound that has an oxygen atom bonded to two organic groups, R-O-R

Question 3

What are Thiols?

Answer 3

Contain an organic portion bonded to an -SH group

Question 4

What are Alkyl halides?

Answer 4

Contain an organic group bonded to a halogen

Question 5

What are the properties of Methyl alcohol?

Answer 5

• Simplest member of alcohol family
• “wood alcohol” (used to be made by heating wood in absence of air)
• Carbon monoxide + hydrogen
• Colorless, miscible with water and toxic to humans when ingested/inhaled

Question 6

What are the properties of Ethyl alcohol?

Answer 6

• Made by fermentation of grain and sugar “grain alcohol”
• In fermentation, starches/complex sugars broken down into simple sugars
• Table wine, beer, liquors

Question 7

What are the properties of Isopropyl alcohol?

Answer 7

• “rubbing alcohol”
• Cools skin through evaporation and causes pores to close

Question 8

Why are alcohols more polar than hydrocarbons?

Answer 8

Due to the electronegative oxygen atom that withdraws electrons from neighbouring atoms -> Polarity -> Hydrogen bonding -> Strong influence on alcohol properties

Question 9

What are the properties of the alcohols with two or more -OH groups?

Answer 9

Can form more than one hydrogen bond -> Higher boiling points + more soluble

Question 10

What happens in dehydration?

Answer 10

Alcohols undergo loss of water (dehydration) on treatment with a STRONG ACID CATALYST -> -OH group is lost from one carbon and an -H is lost from an adjacent carbon to yield an alkene product

Question 11

What happens in Oxidation?

Answer 11

Two hydrogen atoms are removed from alcohol and converted into water during the reaction by the OXIDISING AGENT -> one H comes from the -OH group and other H from the carbon atom bonded to the -OH group -> A CARBONYL COMPOUND is formed

Question 12

What are Primary alcohols converted into?

Answer 12

• Aldehydes (if carefully controlled conditions are used)
• Carboxylic acids (if an excess of oxidant is used)

Question 13

What are Secondary alcohols converted into?

Answer 13

Ketones

[on treatment with oxidising agents]

Question 14

What are the properties of Alcohols and Phenols?

Answer 14

• Very weakly acidic because of the positively polarised OH hydrogen
• Dissociate slightly in aqueous solution and establish equilibria between neutral and anionic forms

Question 15

What are Cyclic ethers?

Answer 15

Compounds that contain the oxygen atom in a ring

Question 16

What happens when Thiols react with mild oxidising agents in water?

Answer 16

They yield disulphides (RS-SR)

[two thirds join together in this reaction, the hydrogen from each is lost and a bond forms between the 2 sulphurs]

Question 17

Why are third important biologically?

Answer 17

They occur as a functional group in the amino acid cysteine

Question 18

What are the simplest halogen-containing compounds?

Answer 18

Alkyl halides

[RX where R is an alkyl group and X is a halogen]

Question 19

Do Ethers hydrogen bond?

Answer 19

NO

they are more alkane-like in their properties

Question 20

Can tertiary alcohols be oxidised?

Answer 20

NO