Carboxylic Acids

Carboxylic Acids:

Carboxylic Acids are homogenous Series/ organic compounds containing the (CO₂H) group.

General Formula:   C_nH_{2n + 1} COOH

Functional Group:

Carboxylic Acids are not HydroCarbons, as they contain Oxygen in their Compounds. Hydro Carbonds are those organic compounds containing only Hydrogen and Carbon.

Properties Of Carboxyic Acids:

• All of them are 100% soluble in water.
• Chemical reaction of Carboxylic Acids are dependent upon C = O (Carboxyl) and H = O (Hydroxyl).
• They are weak acids (partially ionizes in water).

i.e. weaker than inorganic acids – inorganic compounds completely ionize hence more reactive than carboxylic acids.

In Organic Acid:

Organic Acid:

• Carboxylic Acids are partially ionized, to give Hydrogen ions in H₂
• They dissacociate only partially in water to form hydrogen ions.

 

Reactions With Metals:

Carboxylic Acid  + MetalMetal Salt   + Hydrogen

Ethanoic Acid  + Metal Magnesium Ethanoate + H₂

2CH₃COOH  + M_g (CH₃COO)₂M_g   +  H₂

2HCOOH  + Ca (HCOO)₂Ca   +  H₂

 

Reactions With Carbonates + Bi Carbonates:

Carboxylic Acid  + Metal Carbonates Salt   +  CO₂   + H₂O

2CH₃COOH  +   Na₂CO₃2CHCOONa   +   CO₂   + H₂O

HCOOH    +     Na₂CO₃  HCOONa    +    CO₂   + H₂O

Reactions With Basis:

Carboxylic Acid  + Base Salt   + H₂O

2CH₃COOH   + C₄O (CH₃COO)₂C₄       + H₂O

HCOOH   +  C₃OHHCOOCs     +  H₂O

Production Of  Ehtanoic Acid (Carboxylic Acid):

Ethanoic Acid is dropped by the oxidation of Ethanol.

• Using Atmospheric Oxygen:
• By the oxidation of Ethanol in fermented solution with atmospheric oxygen in the presence of certain bacteria.
• When ethanol is left standing in air, bacteria bring about its oxidation to Ethanoic acid – acid fermentation.
• Acid fermentation is used to make vinegar (a dilute solution of Ethanoic acid.) The vinegar is produced from foods such as apples, rice and honey which are first fermented to give ethanol.

 

C₂H₅OH_(l)  +  O_2(g)             CH₃COOH_(l)  + H₂O_(l)

• Using Oxidizing Agents:
• By heating Ethanol with an oxidizing agent such ad acidified Potassium Dichromate(VI)  (K₂Cr₂o₇).
• Ethanol is oxidized much faster by warming the oxidizing agent K₂Cr₂o₇ in the presence of an acid.
• K₂Cr₂o₇ produces atomic Oxygen which more reactive than normal Oxygen (O).
• The Orange K₂Cr₂o₇ solution changes its colour to Green.

• H₂O is also produced as a byproduct while producing ethanol.

Esterification:

Esters are organic compounds formed by the combination of Carboxylic Acis with an Alcohol.

Catalyst – Concentrated Sulphuric Acid (H₂SO₄)

This Reaction is reversible.

H₂0 is produced as a by – product.

Ester is a sweet smelling organic  compound.

Preperation of Ester is known as esterification.

We can add Sodium Hydroxide (NaOH) and heat mixture to obtain Carboxylic acid and alcohol from ester – This is Hydrolysis.

          OH – from acid        H from alcohol    – Ester formation

The two functional groups react with each other. The C of the Carboxyl group bonds to the O of the OH group. The COO group where they join is called ester linkage.

The two molecules have joined by getting rid of a small  molecule, water. This is called condensation reaction.

In Condensation reaction, two molecules join together to form a large molecule, with the loss of a small molecule.

Uses of Esters:

• As a flavouring agent in foods.
• Used in cosmetics.
• Used as a solvent, to dissolve organic compounds that are insoluble in wate. They are volatile, hence they evaporate easily. (painting, ink, glues and nail polish).
• Esters are used in creating vegetable oils.