alcohols and carboxylic acids

alcohol

uses

disinfectants, solvents for paints, alternative sources of fuel, beverages


organic compounds with the formula C(n)H(2n+1)OH. n being the number of carbon atoms

contains hydroxyl (-OH) functional group

ends with -ol

covalent molecules

colourless liquids

low boiling points

soluble in water

properties of alcohol change

increases by CH2

size of molecule decrease

boiling point nicreases

solubility decreases

alcohols vs alkalis

alcohols:

  1. no effect on litmus
  2. covalently bonded
  3. non electrolyte
  4. reacts with organic acids to form esters and water

alkalis:

  1. turns litmus blue
  2. ionically bonded
  3. electrolyte
  4. reacts with mineral acids to form a salt and water

preparation of ethanol (alcohols)

reation of ethene with steam

C2H4 + H2O = C2H5OH

fermentation of glucose

C6H12O6 = 2(C2H5OH) + 2CO2

a beaker full of water at 37 degrees with anaerobic conditions containing a conical flask with a mixture of yeast and glucose

alcohol fermentation is a process in which micro-organisms such as yeast act on carbohydrates like glucose in the absence of oxygen to produce ethanol and carbon dioxide

chemical properties of alcohols

combustion

alcohol + oxygen = carbon dioxide + water vapour

oxidation

alocohol + 2O = carboxylic acid and water

alcohol + O2 = carboxylic acid and water (atmospheric oxygen)

carboxylic acids

organic compounds having general forumla of CnH2n+1COOH

contains carboxyl (COOH) functional group

name ends with Oic

properties of carboxylic acids

increase by CH2

size of molecule increase

boiling point increase

solubility decrease

prepartion of carboxylic acids

oxidation by acidiied potassium manganate

oxidation by atmospheric oxygen

chemical properties of carboxylic acids

carboxylic are weak acids and undergo partial dissociation in water

ethanoic acid = ethanoate ion + H

reaction with reactive metals
2CH3COOH + Mg = (CH3COO)2Mg + H2
(H gets displaced by Mg)

reaction with carbonates
CH3COOH + Na2CO3 = CH3COONa +CO2 + H2O
(ethanoic acid + soidum carbonate = soidum ethanoate +carbon dioxide +water )

reaction with bases
CH3COOH + NaOH = CH3COONa + H2O
( ethanoic acid + sodium hydroxide = sodium ethanoate + water)

esters

physical properties of esters

  1. fairly soluble in water
  2. soluble in organic solvents
  3. neutral to litmus test
  4. low boiling points

reaction with alcohols (esterification)
ethanoic acid + methanol = methyl ethanoate + water
carboxylic acid + alcohols = ester +water

uses

articial food flavourings

manufacture perfumes

solvents for organic compounds