Alcohols Flashcards
Functional group for alcohol
OH
Hydroxyl
The general formula for an alcohol
Cn H2n+1 OH
Primary alcohol (1°)
OH attached to a carbon bonded to one alkyl group
Secondary alcohol (2°)
The OH group is attached to Carbon atom bonded to two alkyl groups
Tertiary alcohol (3°)
The OH is bonded to three alkyl groups
What bonds do alcohol forms
Hydrogen (dotted line) bonds between lone pairs of one oxygen
To the hydrogen of another alcohol
What process makes an alcohol from an Alkene
Hydration
Mechanism for electrophilic addition to make an alcohol
Electron from middle of alkene double bond goes to random H+ (electrophile)
One carbon becomes positive so carbocation
Water
what makes an alcohol molecule polar
O is delta -
H is delta +
so electrons are unevenly distributed in the molecule
making it have a permanent dipole
so it is polar
what makes an alcohols bonding stronger than an alkanes
- alkanes can only have VDW
Alcohols can form two intermolecular forces
- VDW as it is a covalent molecule
- hydrogen bonds due to the presence of a hydroxyl group
hydrogen bonds are strong intermolecular forces than VDW
volatility
how readily a molecule turns to a gas
alcohol physical properties
- soluble in water (due to H bonding)
- higher bp then their corresponding alkane
- less volatile then their corresponding alkane
why are alcohols soluble in water?
- O (s-) in OH can form hydrogen bond with H (s+) in water
- as oxygen is much more electronegative
why does solubility decrease with longer chain?
- the non polar hydrocarbon chain gets longer
- so it disrupts waters structure (difficult to form hydrogen bonds)
- making long chain hydrocarbons less soluble
chemical properties of alcohols?
- undergo combustion to produce CO2 and water
- undergo oxidation
- undergoes elimination
- undergoes nucleophilic substitution
combustion of alcohols
alcohol (liquid) burns in O2 (gas) to make CO2 (g) and water (gas (usually) or liquid)
e.g: methanol
CH3OH(l) + O2(g) → 2CO2(g) + H2O(g)
