Carboxylic Acid Properties

Introduction

Carboxylic acids are an important class of chemical compounds with a wide range of uses. These chemical compounds’ acidic properties make them an important component in our homes and in the food business. The physical properties of carboxylic acids are very useful to the pharmaceutical business. We learned about carboxylic acids’ physical properties in this post. We also learned that carboxylic acids are a grade above their hydrocarbon counterparts.

Carboxylic acids are chemical substances with a carboxylic group in them. The carbon (C) atom is connected to an oxygen (O) atom by a double bond and to a hydroxyl group (OH) by a single bond in the carboxylic functional group. CnH2nO2 is the generic formula for the carboxylic acid homologous series.

Carbonyl compound properties

The carbonyl group can be found in a variety of other functional groups, including aldehydes and anhydrides, as well as ketones and carboxylic acids, to name a few. The important thing to remember is once you see the formula carbon-oxygen double bond (C=O), you can be sure that a carbonyl is present in that functional group.

The polarity of the carbonyl group is another distinguishing feature. A polar material is a compound with both positive and negative charges. Carbonyl’s polarity affects a compound’s properties in two ways: it raises the melting and boiling points and factors that influence the compound’s solubility. Let us now look at how polarity relates to each of these.

Carboxylic acids and their names

You should be rather confident in your ability to name organic molecules by now. Check out Organic Compounds if you aren’t already. However, naming carboxylic acids is actually quite straightforward. Let’s have a look at some of the rules in more detail.

• The suffix -oic acid is found on carboxylic acids.
• To display the molecule’s length, we use the usual root names.
• Carbon 1 in the carbon chain is the carbon that is part of the -COOH functional group.
• Prefixes and numbers are used to denote the position of additional functional groups and side chains on the carbon chain.

Properties of carboxylic acid

Acidity

The most essential attribute of carboxylic acids is their acidity, which is also what gives them their name. Any substance that contributes a hydrogen ion, H+ (also known as a proton), to another compound, referred to as a base, is known as an acid. Carboxylic acids are believed to be stronger acids because they do this far more readily than most other kinds of organic chemicals, although being substantially weaker than any important mineral acids—sulfuric (H2SO4), nitric (HNO3), and hydrochloric (HCl). 

Color and Smell

The majority of carboxylic acids have colourless liquids with unpleasant odours. The odour of inadequately ventilated locker rooms can be found in carboxylic acids with 5 to 10 carbon atoms. Acids containing more than ten carbon atoms are waxlike solids, but their odour decreases as molar mass and volatility increase.

Solubility

Carboxylic acids form hydrogen bonds with water as well as other polar protic solvents easily. When compared to related organic molecules, these acids have a high water solubility. Butyric acid, for example, is infinitely “soluble” in water, whereas the alcohol 1-butanol has a solubility of 7.3g/100mL:

Carboxylic acids containing more than six carbon atoms are water insoluble to sparingly soluble (1g/100mL). Alcohols, such as ethanol, and protic organic solvents, on the other hand, can dissolve carboxylic acids with more than 10 carbon atoms. This is because ethanol may form hydrogen bonds with polar carboxyl groups and participate in van der Waals interactions with non-polar hydrocarbon’ tails.’ As a result, ethanol (and other comparable solvents) can dissolve far greater carboxylic acids than water.

Uses of carboxylic acid

1. Plasticizers and resins are made using 1,2-benzene dicarboxylic acids (phthalic acid).
2. The primary raw material for polyester production is 1,4-benzene dicarboxylic acids (terephthalic acid).
3. The chemical adipic acid is utilized to make nylon.
4. Benzoic acid and several of its salts are antiseptics for the urinary tract.
5. Benzoic acid, either in its pure form or as sodium benzoate, is employed as a food preservative.
6. Ethanoic acid is used to make colours, fragrances, and rayons, among other things.
7.  Ethanoic acid salts are used in paints and some pharmaceuticals.
8. Aluminum and chromium ethanoates (acetates) are utilised as mordants (a substance that attaches dye to the material).

Conclusion

Carboxylic acids are carbon compounds that contain a carboxyl group (–COOH). The carboxyl group is named after the carbonyl group (>C=O) that is attached to the hydroxyl group (–OH).

Depending on the nature of the group to which the –COOH group is attached, carboxylic acids can be classified as aliphatic or aromatic. Aliphatic carboxylic acids are formed when the –COOH group is attached to a H atom or an alkyl group. The general formula RCOOH is used to represent them.

Ethanoic acid (Acetic acid) –CH3COOH, methanoic acid (Formic acid) –HCOOH,  and so on.