Chemistry module 4 -- organic chemistry (Chapter 14 'Alcohols')
What is the combustion in alcohols and it's products
- Alcohols will burn completely in plentiful oxygen supply resulting in CO2 and Water > Reaction is exothermic
Compare the alcohols properties to alkanes with the same general formula?
- Its less volatile ( less rapid evaporation ) - Higher melting points - Greater solubility > However the larger the length of C, the less of difference it is
What is the substitution reaction in alcohols, state the products and the acid involved
- Reaction of alcohols with halides to form haloalkanes and water > Acid involved is H2Ho4 converting the Sodium Halo into Hydrohalogen
What is dehydration in alcohol, the catalyst involved and what type of reaction is it
- Removal of water molecule of alcohol resulting in alkenes ex. Cyclohexanol = Cyclohexane + water > Acids used are H2So4 and H3po4 - It is an example of elimination reaction
State the properties of alcohols
- it is less volatile and higher boiling points because the intermolecular bond holds the molecule together, making it harder to break than alkanes comparing the London forces - It is soluble because the polar property with hydrogen bonding ( OH makes the molecule polar ) - Increase in viscosity (ความหนืด) while the chain lengthens
What is the oxidation in alcohols, state the acids involved and the products
- oxidation can happen in alcohol with the help of Cr2O7 ( K2Cr2O7 acidified with H2So4) > chromium is 3+ - Product is carboxylic acids and water * Tertiary alcohols cannot be oxidised since no double bonds can be created
Why are alcohols polar and alkanes aren't?
Alkanes contains only C-H bonds with very similar electronegativity, compared to alcohols with an O-H bonds.
What example of alcohol is the simplest and it's ability?
CH3OH can create an efficient combustion, name : Methanol
What is the general formula of alcohols?
CnH2n+1OH or CnH2n+2O
Describe the electronegativity in alcohols
It has very weak induced dipole-dipole forces ( London forces ) but the H bonds with the hydroxyl are stronger
What functional group determines an alcohol?
OH group or hydroxyl
How many types of alcohol are there and describe the characteristics
Three including primary, secondary and tertiary Primary - The hydroxyl group is in the either ends of the molecule Secondary - The hydroxyl is bonded between carbon molecules Tertiary - It is bonded in the same carbon that contains a methyl group