C14 Alcohols Flashcards
Functional group of alcohol
-OH (hydroxyl group)
Physical properties of alcohols compared to alkanes
Less volatile
Higher MPs
Greater H2O solubility
Reason for physical properties of alkanes
Non-polar bonds as EN of C + H very similar
IMFs between non-polar molecules are very weak LFs
Reason for physical properties of alcohols
Polar O-H bonds (diff in EN of O and H atoms)
IMFs are very weak LFs but theres also strong HBs between polar O-H
Why do alcohols have higher BPs and lower volatility than alkanes
HBs require more energy to break than weaker LFs in alkanes
Solubility of alkanes in water
Non-polar
Cannot form HBs with H2O
Solubility of alcohols in water
Completely soluble in water
HBs form between polar -OH groups of alcohol + H2O
What happens to solubility as chain length increases
C chain length increases
Influence of -OH becomes smaller
Solubility decreases
What’s a primary alcohol
-OH attached to C that’s attached to 2 H atoms + 1 alkyl group
What’s a secondary alcohol
-OH attached to C that’s attached to 1 H + 2 alkyl groups
What’s a tertiary alcohol
-OH attached to C that’s attached to no H + 3 alkyl groups
What is the colour change when alcohols are oxidised
Orange to green
Dichromate (VI) ions reduced to chromium (III) ions
What do primary alcohols oxidise to
Aldehyde or carboxylic acid
Oxidation of primary alcohol to form aldehyde
Gentle heating
K2Cr2O7/H2SO4
Aldehyde distilled out as it forms
Colour change : orange to green
Oxidation of primary alcohol to form carboxylic acid
Reflux
Excess K2Cr2O7/H2SO4
Orange to green
Form carboxylic acid + water