Difference Between Acetic Acid and Glacial Acetic Acid (With Table)

Acids are the sour substance which when added in water produces (H+) ions. It turns the blue litmus paper to red. Hydrogen ion contains only proton and no electron. Some acids are categorised under strong acid and some under weak acid.

Acetic and glacial acetic acid come under weak acid. These two acid are different from each other in various aspect.

Acetic Acid vs Glacial Acetic Acid

The main difference between acetic acid and glacial acetic acid is level of concentration of acid. Acetic acid is more diluted i.e contains larger concentration of water. Glacial acetic acid is more concentrated and contains less water in comparison to acetic acid.

Acetic acid is a part of carboxylic acid group (weak acid). It is formed naturally by action of bacteria such as Clostridium Acetobutylicum. It is also prepared artificially by air oxidation of acetaldehyde. When food items like fruits are spoiled this result in formation of acetic acid. Vinegar contains acetic acid in major quantity. Basically vinegar is acetic acid but in diluted form.

Glacial acetic acid is in pure form and is very concentrated. It contains very less amount of water. It is called glacial acid because it freezes below temperature of 16°C. This acid is formed by adding acetic acid over frozen acetic acid. This acid is very corrosive and colourless.

Comparison Table Between Acetic Acid and Glacial Acetic Acid

ParametersAcetic acidGlacial acetic acid
MeaningIt is solution of acid and waterIt is concentrated form of acid which freezes below 16°C
ConcentrationDiluted form i.e contains large quantity of waterConcentrated form i.e contains very less amount of water
Formation of
crystals
Cannot form crystalCan form crystals
PreparationAir oxidation of acetaldehydeDipping acetic acid on a frozen form of acetic acid
Freezing pointCannot freezeFreezes below 16°C
UsesUsed as a food preservativeUsed for recrystallization

What is Acetic Acid?

Acetic acid is a important member of carboxylic acid group. Name assigned to acetic acid is ethanoic acid by IUPAC. CH3COOH is the formula of ethonic/acetic acid. It has a pungent odour and is colourless. Molecular mass is 60.052 g/mol. Density of acetic acid is 1.04g/cm³.

Production of acetic acid is done by process of fermentation of ethyl alcohol. The alcohol is oxidised by the oxygen in the air by bacterial action and acetic acid is produced. In industries production of acetic acid is done by catalyst oxidation of acetaldehyde. Acetic acid belong to group of weak acid. So process of electrolysis does not take place. It is found in nature also in plants.

Acetic acid is used in various ways. In home it is used in preparation of food. It is also added to pickle as preservatives. It is also used in cooking and cleaning purpose. The best known form of acetic acid is vinegar. Vinegar is basically acetic acid with large quantity of water i.e very diluted form of acetic acid.

What is Glacial Acetic Acid?

Glacial acid is very concentrated with minimum dilution. Water content in this is very less. It has a special property to freeze below temperature of 16°C . Because of this freezing property it is called glacial acetic acid. It is a liquid which is colourless and very corrosive in nature. Because of its corrosive nature glacial acetic acid needs extra care while handling, as it can cause injuries to skin. Density of glacial acetic acid is 1.05g/cm³.

Glacial acetic acid is laboratory prepared acid. It is formed by dipping solution of acetic acid over a stalactite of glacial acetic acid. It has property of forming crystals. Below a certain temperature glacial acetic acid freezes.

Glacial acetic acid cannot be consumed directly as it is highly corrosive. Crystals of glacial acetic acid is used for purifying water. It is also used as polar-base solvent and in manufacture of Aniline, Terephthalic acid etc. Glacial acetic acid is also used for production of esters.

One should always take certain precaution to avoid any mishap while using glacial acetic acid. Some of the precautions are:
• Always wear a lab coat- Lab coat protects the skin and clothes from any damage, in case acid gets splashed. It acts as a barrier between acid and the person.
• Gloves and safety spectacles- Wearing gloves insure the safety of hand. Safety spectacles prevents any irritation or burning sensation in eyes.
• Diluting acid- While diluting an acid one should always remember to add acid into water and not water into acid. This is the most common mistake made and hence should be strictly avoided. When water is added to acid the temperature of acid and container start rising. The heat produced is so much that the container may break and acid inside get splashed.

Main Differences Between Acetic Acid and Glacial Acetic Acid

  1. Acetic acid is basically a extensively diluted form of pure acid. While glacial acetic acid is without any dilution.
  2. Acetic acid do not freeze. While glacial acetic acid freezes below 16°C.
  3. Acetic acid do not form crystals. While glacial acid forms crystals.
  4. Acetic acid is mildly acidic because of it’s high water content. On the other hand glacial acetic acid is highly corrosive.
  5. Acetic acid is used in preparation of food. But glacial acetic acid cannot be used for this purpose as it is highly corrosive in nature.

Conclusion

Despite having almost same name, this two acids are very different from each other. The main difference is the level of water contained by both of them. Acetic acid contains water in large quantity and in glacial acetic acid water content is vey less. Glacial acetic is in concentrated form. Acetic acid is mild and can also be used for consumption. Due to it’s concentrated form it should be handled with care as it is very corrosive in nature and can cause severe damage if handled carelessly. Also, as the name suggest glacial acid freezes below a certain temperature.

References

  1. https://pubs.acs.org/doi/pdf/10.1021/ja01487a014
  2. http://www.ajnr.org/content/23/6/938.short