Important Acids, Their Uses & MCQs for Competitive Exams
By Home Academy
Introduction
Acids are fundamental chemical substances widely used in industry, medicine, agriculture, and daily life. For competitive exams like JKSSB, SSC, Banking, and UPSC, questions on important acids, their chemical formulas, and uses are frequently asked.
This article provides exam-oriented notes, a structured table, and most expected MCQs.
What is an Acid?
An acid is a substance that:
Releases hydrogen ions (H⁺) in aqueous solution
Turns blue litmus redHas sour taste
This concept is explained under the Arrhenius Theory.
List of Important Acids and Their Uses
| Acid Name | Chemical Formula | Common Name | Major Uses |
|---|---|---|---|
| Hydrochloric Acid | HCl | Muriatic acid | Cleaning metals, digestion in stomach |
| Sulphuric Acid | H₂SO₄ | Oil of vitriol | Batteries, fertilizers, petroleum refining |
| Nitric Acid | HNO₃ | Aqua fortis | Explosives, fertilizers |
| Acetic Acid | CH₃COOH | Vinegar (dilute) | Food preservation, pickling |
| Citric Acid | C₆H₈O₇ | – | Food flavoring, preservatives |
| Tartaric Acid | C₄H₆O₆ | – | Baking powder, food industry |
| Oxalic Acid | C₂H₂O₄ | – | Cleaning agent, rust removal |
| Carbonic Acid | H₂CO₃ | – | Soft drinks |
| Boric Acid | H₃BO₃ | – | Antiseptic, insecticide |
| Phosphoric Acid | H₃PO₄ | – | Fertilizers, soft drinks |
| Formic Acid | HCOOH | – | Rubber processing, preservatives |
| Lactic Acid | C₃H₆O₃ | – | Dairy products, muscle metabolism |
Special Acids Important for Exams
1. Aqua Regia
Mixture of HCl and HNO₃ (3:1 ratio)
Dissolves noble metals like gold and platinum2. Oleum
H₂S₂O₇ (fuming sulphuric acid)
Used in manufacture of sulphuric acidAcids in Daily Life
| Substance | Acid Present |
|---|---|
| Lemon | Citric acid |
| Vinegar | Acetic acid |
| Curd | Lactic acid |
| Ant sting | Formic acid |
| Soft drinks | Carbonic acid |
Most Important MCQs (Exam Focused)
1. Which acid is present in vinegar?
A. Citric acid
B. Acetic acid
C. Lactic acid
D. Formic acid
Answer: B. Acetic acid
2. Which acid is used in car batteries?
A. Nitric acid
B. Hydrochloric acid
C. Sulphuric acid
D. Acetic acid
Answer: C. Sulphuric acid
3. Aqua regia is used to dissolve:
A. Iron
B. Copper
C. Gold
D. Zinc
Answer: C. Gold
4. Which acid is found in lemon?
A. Acetic acid
B. Citric acid
C. Tartaric acid
D. Oxalic acid
Answer: B. Citric acid
5. Which acid is responsible for sour milk?
A. Formic acid
B. Lactic acid
C. Acetic acid
D. Carbonic acid
Answer: B. Lactic acid
6. Which acid is used in explosives?
A. Nitric acid
B. Boric acid
C. Carbonic acid
D. Citric acid
Answer: A. Nitric acid
7. Which acid is present in ant sting?
A. Citric acid
B. Formic acid
C. Acetic acid
D. Oxalic acid
Answer: B. Formic acid
8. Which acid is used as an antiseptic?
A. Boric acid
B. Nitric acid
C. Sulphuric acid
D. Hydrochloric acid
Answer: A. Boric acid
9. Chemical formula of phosphoric acid is:
A. H₃PO₄
B. H₂SO₄
C. HNO₃
D. HCl
Answer: A. H₃PO₄
10. Which acid is used in baking powder?
A. Tartaric acid
B. Acetic acid
C. Formic acid
D. Citric acid
Answer: A. Tartaric acid
Previous Year Question Trend
Match the following (Acid vs Uses)
Identify acid from formulaDaily life acid questions (very common)
Industrial use-based MCQs
Quick Revision Points
H₂SO₄ → Battery acid
HNO₃ → ExplosivesCH₃COOH → Vinegar
HCl → Gastric juice
H₃PO₄ → Fertilizers
HCOOH → Ant sting
Conclusion
Understanding acids, their formulas, and uses is essential for scoring well in competitive exams. Questions are usually direct, factual, and repeated, making this topic a high-scoring area.
Regular revision of tables and MCQs will ensure strong command over this section.
Disclaimer
These notes are prepared by Er Afzal Malik, Founder of Home Academy, for competitive exam aspirants. We strive to provide accurate and reliable content; however, we are not responsible for any unintended errors or consequences arising from its use.