Carboxylic acids have the general formula R-COOH. They are weak acids that only partially dissociate in water. Common properties include being colorless liquids or solids with sharp odors and high boiling points. Alcohols can be oxidized to form carboxylic acids using potassium dichromate and sulfuric acid. Carboxylic acids react with metals to form salts and hydrogen gas, with carbonates to form salts, carbon dioxide and water, and with bases to form salts and water. They also undergo esterification reactions with alcohols to form esters and water. Common uses include as preservatives and flavorings in food and in making soaps, drugs, dyes,

1.  Carboxylic acids are weak acid
 General Formula:
 Functional Group:
 Naming of carboxylic acid:
CnH2n+1COOH
Carboxyll
Number
of Carbon
1 2 3 4 5 6
Molecular
formula
HCOOH CH3COOH C2H5COOH C3H7COOH C4H9COOH C5H11COOH
Name
methanoic
acid
ethanoic
acid
propanoic
acid
butanoic
acid
pentanoic
acid
hexanoic
acid
n = 0, 1, 2, ...
Carboxylic Acids

2. Physical
Properties of
Carboxylic
Acids
Colour
- Colourless
liquid
State
- Larger molecules
(C10 above) are
wax-like solids
Odour
- sharp/
unpleasant smell
Boiling point
- High boiling
point
Solubility
- Simple molecules
are very soluble in
water
- Due to water
molecule being
strongly attracted to
the – COOH group
- Solubility ↓ when
number of C ↑

3.  Alcohols can be oxidised to carboxylic acids
using potassium dichromate(VI) solution in
the presence of dilute sulphuric acid.
 Chemical Equation below represent the
reaction.
C2H5OH+ 2[O] → CH3COOH + H2O
Preparing Carboxylic Acids

4. Alcohols can be
oxidised to produce
carboxylic acid
when react with
oxidising agents

5. a. Acid properties
 CH3COOH is a weak monoprotic acid
 Only one hydrogen atom can ionize in water to
produce H+ ion
 Partially dissociate in water
 Turn moist blue litmus → red
 React slowly with metals, bases and carbonates
CH3COOH ↔ CH3COO- + H+
Ethanoic acid Ethanoate ion
Chemical Properties Of Carboxylic Acids

6. b. Reaction with metals
 Carboxylic acid + metal → salt + H2
c. Reaction with carbonates
 Carboxylic acid + carbonates → salt + CO2 + H2O
2CH3COOH + Zn → Zn(CH3COO)2 + H2
Ethanoic acid Zinc ethanoate
2CH3COOH + CaCO3 → Ca(CH3COO)2 + CO2 + H2O
Ethanoic acid Calcium ethanoate

7. d. Reaction with bases
 Carboxylic acid + bases → salt + H2O
CH3COOH + NaOH → CH3COONa + H2O
Ethanoic acid Sodium ethanoate
2CH3COOH + CuO → Cu(CH3COO)2 + H2O
Ethanoic acid Copper (II) ethanoate

8. e. Reaction with alcohols (esterification)
 Carboxylic acid + alcohol → ester + H2O
 Catalyst: Concentrated H2SO4
CH3COOH + C4H9OH → CH3COOC4H9 + H2O
Ethanoic acid Butan-1-ol Buthyl ethanoate

9.  Ethanoic acid (acetic acid)
• As a flavouring
• As a preservative
• Used with other chemicals to make drugs, dyes,
paints, insecticides and plastics
 Methanoic acid (formic acid)
• Used to coagulate latex
 Fatty acids (long-chain carboxylic acids)
• Used in making soaps
 Benzoic acid
• Preservative in food
Uses of Carboxylic Acids