Alcohols

Question 1

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Explain 2 Main properties of alcohols!

Answer 1

1. Higher BP/MP than Alkanes: Due to oplar bonds of OH group, able to form strong hydrogen Bonds, as well as L.Forces
2. Soluble: OH group able to form hydrogen bonds with H2O molecules
3. HENCE, alcohols are LESS VOLATILE, more energy used to break H Bonds

Question 2

How can we classify alcohols?

Answer 2

1. Primary: Carbon atom bonded to 2 hydrogens, 1 alkyl groups
2. Secondary: Carbon atom bonded to 1 hydrogens, 2 alkyl groups
3. Tertiary: Carbon atom bonded to NO hydrogens, 3 alkyl groups

Question 3

How does alcohol combustion occur?

Answer 3

1. Undergoes complete combustion to form the ReGuLaR CO2 and H2O….
2. More carbon = more energy erleased per mole

JUST LIKE ALKENES!!!!!!!!!!!!!

Question 4

How to use oxidising agents with alcohols…..?

Answer 4

1. ACIDIFIED POTASSIUM DICHROMATE! (H2SO4)
2. Dichromate ions = Orange, Cr3+ = Green, AFTER BEING REDUCED!
3. Colour change signifies complete oxidation of alcohol (to product)

Question 5

Define reflux

Answer 5

• Heating strongly under continual evaporation and condensation of reaction mixture back into original container (ensuring no loss of gaseous intermidiate products)

Question 6

First Product of Primary Alcohol oxidation process…

Answer 6

1. Acidified Oxidising agent provides O2 to alcohol
2. 2 Hydrogen atoms removed
3. Will form ALDEHYDE + H2O under DISTILLED CONDITIONS, to separate aldehyde from alcohol (lower MP/BP)!!, to condensing tube….

Question 7

Second Product of Primary Alcohol oxidation process…

Answer 7

1. EXCESS Acidified Oxidising agent (ensures full oxidation!) provides O2 to alcohol
2. Will form CARBOXYLIC ACID + H2O under REFLUX CONDITIONS, to oxidise all aldyhyde intermediates and alcohols present!!

Question 8

Product of Secondary Alcohol oxidation process…

Answer 8

1. EXCESS Acidified Oxidising agent (ensures full oxidation!) provides O2 to alcohol
2. Will form KETONE + H2O under REFLUX CONDITIONS, to oxidise all alcohols present!!
3. Can NOT oxidise further, as no present hydrogen can be removed on C attached to previous -OH group

Question 9

Product of Tertiary Alcohol oxidation process…

Answer 9

• NO OXIDATION REACTION!
• Acidifies dichromate solution remains orange, as no present hydrogen can be removed on C attached to -OH group

Question 10

Product of Dehydration of alcohols process…

Answer 10

1. Example of ELIMINATION REACTION!!
2. H2O removed from alcholol’s (-H and -OH groups)
3. Will form ALKENE + H2O under REFLUX CONDITIONS, via H2SO4 or H3PO4!!
4. 1 reactant, 2< products fromed = ELIMINATION ALWAYS

Question 11

ProductS of Subsitution of alcohols process…

chek chek CHEK!

Answer 11

1. uses SODIUM HALIDE
2. Will form ALCOHOL with HALO-GROUP under REFLUX CONDITIONS, with H2SO4
3. SODIUM HALIDE reacts with SULFURIC ACID to form HYDROGEN HALIDE and Sodium Hydrogensulfate (useless by-product icl)
4. new HALOGEN HALIDE then reacts with the alcohol for the halo-product!! (OH group SUBBED for HALO one)

BOTH REACTION OCCUR SIMULTANEOUSLY!!!!!!