3E1 2012 Group 9

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Organic acids

Introduction

Have you ever wondered what organic acids are? Or what are the differences between an organic acid and an acid? Allow this Wiki to explain to you in detail about organic acids.

Definition

Organic acids are compounds with acidic properties and they are originally found in animals or plants but now contain other compounds of carbon.

Comparing organic acids to acids

Similarities

Both have properties of acids.
Both are miscible in water.
Both contain H+ ions in their respective chemical formulas.
Both lose H+ ions (Protons) when they dissociate or when undergoing ionic bonding.
Both dissociates in water.

Differences

Organic acids are generally classified as weak acids and do not dissociate completely in water while acids can be widely classified into weak and strong acids depending on the respective pHs of the acids. Depending on whether an acid is weak or strong, it will not dissociate completely (weak acid) or it will dissociate completely (strong acid) respectively.

Organic acids can be found in animals and plants while some acids cannot be found in animals and plants depending on its acidity level and whether it will harm the animal or plant.

Organic acids are in general are soluble in organic solvents while acids can be soluble or insoluble in various solvents depending on what acid is used to dissolve in the solvent. Some acids are insoluble in organic solvents.

Substances researched

These are the organic acids that our group has researched:

Lactic acid
Formic acid
Benzoic Acid
Acetic Acid

Lactic acid

Basic Info

colorless, odorless, liquid
2-Hydroxypropanoic acid
C3H6O3
pH 3.86
The structural formula is represented by the picture below.

Ions

Loses 1 proton to form an anion - lactate ion, with formula of CH3CH(OH)COO⁻

Functions, Uses

Lactic acid plays a critical role in generating energy during exercise. It provides fuel for many tissues, helps use dietary carbohydrates, and serves as a fuel for liver production of glucose and glycogen.

Interesting facts

Athletes and physiologists have used to think that lactic acid is a primary cause of fatigue during high-intensity exercise. However, recent studies have shown that lactic acid actually does the opposite, and prevents muscle fatigue.
Lactic acid present on the skin attracts mosquitoes.

Formic acid

Basic Info

It is otherwise known as methanoic acid
It is a colourless liquid, highly pungent, penetrating odur.
Its chemical formula is HCOOH or HCO2H.
The structural formula is represented by the picture below.
pH-about 2-3
The structural formula is represented by the picture below.

Ions

It loses a proton(hydrogen) to form an anion-called formate or methanoate ion with the chemical formula CHOO⁻ or HCOO⁻

Functions and Uses

It is used as a preservative and anti-bacterial agent in livestock feed.
It is used in cleaning products like toilet bowl cleaners , etc.
It allows fermentation to take place faster and at lower temperatures.
It is natural in venom of bees and ant stings for defensive measures against predators and also to attack prey.

Interesting Facts

It is actually a natural occurrence in the atmosphere due to forest emissions.
It is naturally found in venom of bees and ant stings.
Giant anteaters, unlike most mammals, produce formic acid instead of hydrochloric acid due to their abundance in diet.

Benzoic Acid

Basic information

Chemical name: Carboxybenzene
Chemical formula: C7H6O2
pH 2.1
It is slightly soluble in water, soluble in ethanol and very slightly soluble in benzene and acetone.
Its aqueous solution is weakly acidic.
Benzoic Acid activates Bromelain
The structural formula is represented by the picture below.

Ions

When the crystalline Benzoic Acid crystals are dissolved in water, hydrogen ions (H+) ions are produced.

Uses and Functions

Used as a chemical standard to determine the heat of capacity of bomb calorimeters.
Used as food preservatives (Benzoic acid helps to stop the growth of mold, yeast and bacteria)
Has medicinal properties
Benzoic acid is combined with chloride and phosphorus to make chemicals

Interesting facts

It occurs naturally in a number of fruits, including cranberries, prunes, greengages, cloudberries, and in cinnamon.
Cloudberries contain so much benzoic acid that they can be stored for long periods of time without bacterial or fungal spoilage.
Even though Benzoic Acid is a good preservative, it has its harmful effects too.( known to affect the liver and kidney, along with more serious issues like excessive cyclamate when taken in excess.)