Important Examples of Carboxylic Acids

Carboxylic acids are widely present in nature and industry. They vary in structure, properties, and applications. Below are some important examples:

1. Formic Acid (HCOOH)

• Simplest carboxylic acid.
• Found in ant and bee stings.
• Used as preservative in livestock feed.

2. Acetic Acid (CH₃COOH)

• Main component of vinegar.
• Used in synthetic fibers, plastics, food additive (E260).
• Strong pungent odor, miscible with water.

3. Propionic Acid (CH₃CH₂COOH)

• Found in dairy products by bacterial fermentation.
• Preservative in bread and baked goods.

4. Butyric Acid (CH₃CH₂CH₂COOH)

• Present in rancid butter, unpleasant smell.
• Produced in human colon by bacterial fermentation.

5. Valeric Acid (CH₃(CH₂)₃COOH)

• Found in valerian root (herbal medicine).
• Used in perfumes and pharmaceuticals.

6. Oxalic Acid – (COOH)₂

• Dicarboxylic acid found in spinach and rhubarb.
• Used as cleaning agent, rust remover.
• Toxic in large quantities.

7. Citric Acid – C₆H₈O₇

• Found in citrus fruits.
• Key in Krebs cycle (metabolism).
• Used in food preservation, flavoring, cleaning.

8. Benzoic Acid – C₆H₅COOH

• Aromatic acid, food preservative (E210).
• Used in dyes, perfumes, pharmaceuticals.

9. Lactic Acid – CH₃CH(OH)COOH

• Produced in muscles during anaerobic respiration.
• Used in cosmetics, food, biodegradable plastics.

10. Salicylic Acid – C₆H₄(OH)COOH

• Precursor of aspirin.
• Used in acne, warts, and skin treatments.

Conclusion: These examples show the diversity of carboxylic acids, highlighting their importance in food, medicine, metabolism, and industry.

MCQs on Carboxylic Acids

1. The main component of vinegar is:
   a) Formic acid
   b) Acetic acid
   c) Citric acid
   d) Lactic acid
   Answer: b) Acetic acid
2. Which acid is present in ant stings?
   a) Oxalic acid
   b) Formic acid
   c) Butyric acid
   d) Citric acid
   Answer: b) Formic acid
3. Which acid is used in aspirin preparation?
   a) Salicylic acid
   b) Benzoic acid
   c) Propionic acid
   d) Lactic acid
   Answer: a) Salicylic acid

Fill in the Blanks

• ________ acid is responsible for the sour taste in citrus fruits. Citric acid
• Butyric acid is found in ________. rancid butter
• Oxalic acid is toxic and occurs in ________. spinach, rhubarb

Quick Quiz

Q: Which two carboxylic acids are commonly used as food preservatives?

A: Benzoic acid (E210) and Acetic acid (vinegar).

FAQs on Carboxylic Acids

Q1: Which carboxylic acid is present in vinegar?
A: Acetic acid (CH₃COOH).

Q2: Which acid is used in the preparation of aspirin?
A: Salicylic acid.

Q3: Why is oxalic acid considered harmful?
A: Because it is highly acidic and toxic in high amounts, binding calcium in the body.