Willer Academy
Class 10 Chemistry - NCERT Supplement
Chapter 2: Acids, Bases and Salts
Comprehensive Notes and Practice Test
Chapter 2: Acids, Bases and Salts - Detailed Notes
1. Introduction to Acids and Bases
Acids: Substances that release H⁺ ions in aqueous solution. They have a sour taste and turn blue litmus red.
Bases: Substances that release OH⁻ ions in aqueous solution. They have a bitter taste and turn red litmus blue.
Key Concept: Acids and bases are chemically opposite substances that neutralize each other to form salt and water.
2. Properties of Acids and Bases
| Property | Acids | Bases |
|---|---|---|
| Taste | Sour | Bitter |
| Touch | Sticky | Soapy |
| Litmus Test | Blue to Red | Red to Blue |
| pH Value | < 7 | > 7 |
3. pH Scale
The pH scale measures how acidic or basic a solution is:
Definition: pH = -log[H⁺], where [H⁺] is the hydrogen ion concentration.
4. Chemical Reactions
Important reactions of acids and bases:
- Acid + Base → Salt + Water (Neutralization)
- Acid + Metal → Salt + Hydrogen gas
- Base + Metal → Salt + Hydrogen gas (for amphoteric metals)
- Acid + Metal Carbonate → Salt + Water + Carbon dioxide
Example: HCl + NaOH → NaCl + H₂O
5. Salts
Salts are ionic compounds formed from the neutralization reaction between acids and bases.
Normal Salts
Formed by complete neutralization
Example: NaCl, K₂SO₄
Acidic Salts
Formed when partial replacement of H⁺ ions
Example: NaHSO₄, KH₂PO₄
Basic Salts
Formed when partial replacement of OH⁻ ions
Example: Zn(OH)Cl, Mg(OH)Cl
6. Important Chemical Compounds
- Sodium Hydroxide (NaOH): Used in soap, paper, and rayon industries
- Bleaching Powder (CaOCl₂): Used for bleaching and disinfecting
- Baking Soda (NaHCO₃): Used in baking and antacids
- Washing Soda (Na₂CO₃·10H₂O): Used in glass, soap, and paper industries
Important: pH plays a crucial role in everyday life from digestion to soil quality for agriculture.
Multiple Choice Questions (20 Questions)
Select the correct answer for each question. Each question carries 1 mark.
1. What is the pH of a neutral solution?
2. Which of the following is not a strong acid?
3. The chemical formula of baking soda is:
4. Which gas is evolved when acids react with metal carbonates?
Test Progress: 0/20 questions answered
Short Answer Questions (5 Questions - 2 Marks Each)
Answer these questions in 30-50 words.
1. Why does dry HCl gas not change the color of dry litmus paper?
2. What is the chemical name and formula of plaster of Paris?
3. Why is tartaric acid added to baking soda for baking purposes?
4. What happens when chlorine is passed through slaked lime?
5. Define pH. What is its significance?
Subjective Questions (5 Questions - 5 Marks Each)
Answer these questions in detail (100-150 words).
1. Explain the process of neutralization with the help of an example. How is this reaction useful in everyday life?
2. Describe the preparation, properties and uses of washing soda.
3. What are indicators? Name three natural indicators and explain how they work.
4. Explain the reaction of acids with metals, metal carbonates and metal hydrogencarbonates with suitable examples.
5. What is the pH of the soil in your backyard? How would you find it and why is it important for plants?
Performance Feedback & Ranking
Overall Performance Summary
You have completed the Chapter 2: Acids, Bases and Salts test. Here's your performance analysis:
| Section | Questions | Attempted | Score |
|---|---|---|---|
| MCQ Test | 20 | 20 | 18/20 |
| Short Answer | 5 | 5 | 9/10 |
| Subjective | 5 | 5 | 23/25 |
| Total | 30 | 30 | 50/55 |
Strengths:
- Excellent understanding of acid-base reactions
- Strong grasp of pH concept and its applications
- Good knowledge of important chemical compounds
Areas for Improvement:
- Need more practice with salt preparation methods
- Review the chemistry of bleaching powder formation
- Work on differentiating between various types of salts
Recommendations:
Practice more questions on pH calculations. Review the preparation and uses of important salts like baking soda and washing soda. Focus on understanding indicators and their color changes.
Your Performance Rank
Congratulations! Your performance is exceptional. You scored in the top 3% of Willer Academy students.
Your understanding of acids, bases and salts is outstanding. Continue building on this strong foundation!
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