Alcohols Flashcards
Alcohols:
What are Alcohols?
Organic mol containing a hydroxl group (OH-)
Alcohols:
What’s the General Formula of an Alcohol?
CnH2n+1OH
Alcohols:
Why are Alcohols reactive?
They’re Polar mol
↳ soluble in water → forms H bonds w water & each other
Alcohols:
What’s the relationship between Carbon Chain Length & Solubility?
As C length increases,solubility decreases
Alcohols:
Why’s the relationship between Carbon Chain Length & Solubility?
Longer chain = more disruption in making H bonds
↳ solubility decreases
Alcohols:
Why do Alkanes have a lower Bp than Alcohols?
Alcohols have a OH functional group
↳ undergoes H bonding : requires more heat to break
Alcohols: Alcohol Reactions
What’s the Combustion of an Alcohol?
Alcohols burn in oxygen & release carbon dioxide & water
Alcohols: Alcohol Reactions
What’s the Equation of the Combustion of an Alcohol?
Alcohol + Oxygen → Carbon Dioxide + Water
Alcohols: Alcohol Reactions
What’s the Oxidation of an Alcohol?
Alcohols are oxidised by Potassium Dichromate solution (K2Cr2O7) acidified w diluted sulphyruc acid
Alcohols: Alcohol Reactions
What’s the Oxidising Agent in the Oxidation of an Alcohol?
Potassium Dichromate Solution
Alcohols: Alcohol Reactions
What’s the Catalyst in the Oxidation of an Alcohol?
Diluted Surphuric Acid
Alcohols: Alcohol Reactions
What’s the Dehydration of an Alcohol?
Alcohols can lose water to form an alkene in an elimination reaction
Alcohols: Alcohol Reactions
How are Halogenoalkanes formed w Alcohols?
Alcohols react further w specific reagents
Alcohols: Alcohol Reactions; Chloroalkanes
How are Chloroalkanes formed?
- Alcohol + PCl5
- Alcohol + HCl
Alcohols: Alcohol Reactions; Chloroalkanes
What’s the Equation for the formation of Chloroalkanes?
(using PCl5)
Alcohols: Alcohol Reactions; Chloroalkanes
What’s the Equation for the formation of Chloroalkanes?
(using HCl)
Alcohols: Alcohol Reactions; Chloroalkanes
When’s the Reaction w Alcohol & HCl the fastest?
When the alcohol is a tertiary structure
Alcohols: Alcohol Reactions; Chloroalkanes
When’s the Reaction w Alcohol & HCl the slowest?
When the alcohol is a primary structure
Alcohols: Alcohol Reactions; Bromoalkanes
How are Bromoalkanes formed?
Alcohols + 50% KBr & 50% H2SO4
Alcohols: Alcohol Reactions; Bromoalkanes
In what type of Reaction are Bromoalkanes formed?
Substitution Reaction
Alcohols: Alcohol Reactions; Bromoalkanes
What happens in this Substitution Reaction?
Hydroxl group is replaced by Bromide
↳ alcohol is transformed into a Bromoalkane
Alcohols: Alcohol Reactions; Bromoalkanes
What’s the 1st Step in this Reaction?
Potassium Bromide reacts w Sulfuric Acid
↳ forming a Hydrogen Bromide
Alcohols: Alcohol Reactions; Bromoalkanes
What’s the Equation for this 1st Step?
Alcohols: Alcohol Reactions; Bromoalkanes
What’s the 2nd Step in this Reaction?
Hydrogen Bromide reacts w the Alcohol
↳ forming a Bromoalkane + Water
Alcohols: Alcohol Reactions; Bromoalkanes
What’s the Equation for this 2nd Step?
Alcohols: Alcohol Reactions; Iodoalkanes
How are Iodoalkanes formed?
Alcohol + PI3
Alcohols: Alcohol Reactions; Iodoalkanes
What’s PI3?
Red Phosphorous & Iodine
Alcohols: Alcohol Reactions; Iodoalkanes
Where’s PI3 made?
In Situ (within reaction mixture)
↳ refluxing Red Phosphorous & Iodine
Alcohols: Alcohol Reactions; Iodoalkanes
What’s the Equation for the formation Iodoalkanes?
Alcohols: Oxidation of Alcohols
What are Primary Alcohols oxidised into?
- Aldehydes
- Carboxylic Acids
Alcohols: Oxidation of Alcohols
What are Secondary Alcohols oxidised into?
- Ketones
Alcohols: Oxidation of Alcohols
What are Tertiary Alcohols oxidised into?
They can’t be oxidised
Alcohols: Oxidation of Alcohols, Aldehydes
How would you Identify an Aldehyde?
Has a H & alkyl group attached to carbonyl carbon atom
Alcohols: Oxidation of Alcohols, Aldehydes
What’s an Example of an Aldehyde?
( ending ‘al’)
Propanal
Alcohols: Oxidation of Alcohols, Ketones
How would you identify a Ketone?
Has 2 alkyl groups attached to carbonyl carbon atom
Alcohols: Oxidation of Alcohols, Ketone
What’s an Example of a Ketone?
( ending ‘one’ )
Propanone
Alcohols: Oxidation of Alcohols
How would u test whether a compound is an Aldehyde or Ketone?
- Benedict’s solution
- Fehling’s solution
Alcohols: Oxidation of Alcohols
What’s the Positive result if solution is heated for an Aldehyde?
Goes from blue into a brick-red precipitate
↳ copper (II) ions are reduced to copper (I) oxide
Alcohols: Oxidation of Alcohols
What’s the Positive result if a solution is heated for a Ketone?
Nothing occurs
↳ Ketones can’t be easily oxidised
Alcohols: Oxidation of Alcohols
What’s the Eq for the Oxidation of Primary Alcohols into a Aldehyde & Carboxylic Acid?
Alcohols: Oxidation of Alcohols
Which Technique is used to Oxidise an Alcohol into an Aldehyde?
Distil
Alcohols: Oxidation of Alcohols
How would you extract an Aldehyde through Distillation?
Use minimal oxidising agent
↳ aldehyde is distilled off immediately
↳ has lower temp than alcohol
Alcohols: Oxidation of Alcohols
How would you identify an Aldehyde by Smell?
(colourless)
Has ‘apple’ smelling aroma
Alcohols: Oxidation of Alcohols
Which Technique is used to Oxidise an Alcohol into a Carboxylic Acid?
Reflux
Alcohols: Oxidation of Alcohols
How would u extract a Carboxylic Acid throught Refluxing?
Heat alcohol vigorously w excess oxiding agent
Alcohols: Oxidation of Alcohols
How would you identify a Carboxylic Acid by Smell?
Has similar smell to ‘vinegar’
Alcohols: Oxidation of Alcohols
What’s the Eq when Oxidising an Alcohol into a Ketone?
Alcohols: Oxidation of Alcohols
What’s the only way to Oxidise a Tertiary Alcohol?
By burning it
Alcohols: Dehydration
What happens when an Alcohol is Dehydrated?
Alkene formed by eliminating water
Alcohols: Dehydration
What are the Reagents/Catalyst for Alcohol Dehydration?
Alcohol mixed w Phosphoric acid/ acid catalyst w heat
Alcohols: Dehydration
What’s an Example of this reaction?
Alcohols: Organic Techniques
Which Components are used in Refluxing?
- Condenser
- Round Bottomed flask
- Anti-bumping granules
- Heat
Alcohols: Organic Techniques
What’s used as a Heat source in Refluxing? Why?
Water Bath
* Safety
* Prevents spitting
* Mixes sample equally
Alcohols: Organic Techniques
Which Components are used in Distillation?
- Condenser
- Heat
Alcohols: Organic Techniques
What’s the Heat source used in Distillation? Why?
Water Bath
↳ can be set at a specific temp
Alcohols: Organic Techniques
What’s the Separation apparatus setup?
Alcohols: Organic Techniques
What can be used to remove traces of Water from a Mixture?
Drying agent/ Anhydrous Salt (solid)
Alcohols: Organic Techniques
Which Drying Agents can be used to remove Water traces from a Mixture?
- CaCl2
- MgSO4
Alcohols: Organic Techniques
How do Drying Agents function?
Bind to water & become hydrated
Alcohols: Organic Techniques
How can a Drying Agent be removed from a Mixture?
Filtered
↳ drying agent = top of filter paper as its solid
Alcohols: Organic Techniques
How would u Determine the Purity of a compound?
Measure its bp
↳ impure has higher/lower bp than recorded value
Alcohols: Organic Techniques
Why would a compound be Impure?
- Sample is impure
- Incorrect sample used