3.5 - Alcohols 2 Flashcards
Observation is Aldehyde present & Oxidised w/ Tollens’ Reagent?
Ag⁺ + e⁻ |> Ag(s)
Silver Mirror
Oxidation product of Secondary Alcohols?
Ketone
What can the Organic tests be used to Confirm?
Presence & Identity of Organic Impurities
Oxidation product of Primary Alcohols?
Aldehyde
Carboxylic Acid
Organic product when a Carboxylic Acid reacts with Na₂CO₃?
Carboxylate Salt
e.g. Sodium Ethanoate
Will Ketones React with either Tollens’ Reagent or Fehling’s solution?
No - Ketones cannot be oxidised
Oxidising Agent in Oxidation of Alcohols?
Acidified Potassium Dichromate
H⁺/Cr₂O₇²⁻
General Equation of Oxidation of Aldehyde?
R-C(=O)-H + [O] |> R-C(=O)-OH
Test for Presence of Aldehydes?
Mild Oxidising Agents:
e. g. Tollens’ Reagent
e. g. Fehling’s solution
Observation when Carboxylic Acid reacts with Na₂CO₃?
Fizz
CO₂ produced
General Equation of Oxidation of Secondary Alcohols?
R-C-(H,OH)-R + [O] |> R-C(=O)-R + H₂O
Can Ketones be Oxidised further?
No
Why is the Product of Oxidation of a Primary Alcohol most likely to be an Aldehyde when formed through Immediate Distillation?
Aldehyde has Lower Boiling Point than Alcohol
(pd-pd weaker than H-bond)
Turns into a gas & cannot react further
Observations for Oxidation of Secondary Alcohols
Orange |> Green
In Organic Chemistry, what is Oxidation?
Creation of more C-O bonds
General Equation for Oxidation of a Primary Alcohol to a Carboxylic Acid?
R-CH₂-OH + 2[O] |> R-C(=O)-OH + H₂O
How can H⁺/Cr₂O₇²⁻ be used to identify Tertiary Alcohols?
No Observable Change
Observations for Oxidation of a Primary Alcohol to an Aldehyde?
Orange |> Green
How is Fehling’s solution formed?
Add Fehling’s 1 to Fehling’s 2
Copper Sulfate to Potassium Sodium Tartrate
Organic product when Aldehyde present & Oxidised with Fehling’s solution?
Carboxylic Acid
What is formed when a Secondary Alcohol is Oxidised?
Ketone
General Equation for reaction of Carboxylic Acid with Na₂CO₃?
2R-C(=O)-OH + Na₂CO₃ |> 2R-C(=O)-O⁻Na⁺ + CO₂ + H₂O
Test for Presence of a Carboxylic Acid?
Add Sodium Carbonate
Na₂CO₃
Organic product when Aldehyde present & Oxidised with Tollens’ Reagent?
Carboxylic Acid
Observations if Aldehyde present & Oxidised with Fehling’s solution?
Cu²⁺(aq) |> Cu₂O(s)
Blue solution |> Brick red ppt
Oxidation product of Tertiary Alcohols?
Not Oxidised
No Reaction
No H on Carbon to remove
How is the Carboxylic Acid removed from the reaction mixture?
Distillation
How is an Aldehyde denoted in naming, structural formula & numbering?
-Al
-CHO
No number, always named as end Carbon
Reagents & Conditions for Oxidation of Secondary Alcohols?
Acidified Potassium Dichromate (VI)
Reflux
General Equation for Oxidation of a Primary Alcohol to an Aldehyde?
R-CH₂-OH + [O] |> R-CHO + H₂O
Reagents & Conditions for Oxidation of a Primary Alcohol to a Carboxylic Acid?
Acidified Potassium Dichromate (VI)
Reflux
In balanced equations, what can the Oxidising Agent be simplified to?
[O]
Observations for Oxidation of a Primary Alcohol to a Carboxylic Acid?
Orange |> Green
Reagents & Conditions for Oxidation of a Primary Alcohol to an Aldehyde?
Acidified Potassium Dichromate (VI)
Distillation
How is Tollens’ Reagent formed?
Add NaOH to AgNO₃
until brown precipitate formed
Add NH₃ until ppt dissolves
Why is the product of Oxidation of a Primary Alcohol most likely to be a Carboxylic Acid when formed through Reflux?
Aldehyde is Recondensed back into the flask so further Oxidation can occur
Define: Reflux
Boiling without gas escaping
