10th Class Chemistry Chapter 10 Notes | Get Now
10th Class Chemistry Chapter 10 Notes cover Acids, Bases and Salts — one of the most scoring chapters in the Punjab Board matric syllabus. This chapter explains different theories of acids and bases, how pH is calculated, and the properties, preparation, and uses of salts. These notes break down every concept in simple language so students can revise quickly before exams.
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Whether you’re solving numericals on pH or memorizing definitions for short questions, these 10th Class Chemistry Chapter 10 Notes will help you understand the chapter without confusion.
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What You Will Learn in This Chapter
Chapter 10 of 10th Class Chemistry introduces students to:
- Arrhenius concept of acids and bases
- Bronsted-Lowry concept and conjugate acid-base pairs
- Lewis concept of acids and bases
- Chemical properties and uses of acids and bases
- pH, pOH, and the pH scale
- Indicators and their color changes
- Salts: types, preparation, and uses
Let’s explore each topic in detail as part of these 10th Class Chemistry Chapter 10 Notes.
Arrhenius Concept of Acids and Bases
According to the Arrhenius concept, an acid is a substance that dissociates in water to give hydrogen ions (H⁺), while a base dissociates in water to give hydroxide ions (OH⁻).
- Acids: HCl, HNO₃, H₂SO₄, CH₃COOH
- Bases: NaOH, KOH, Ca(OH)₂
Limitations of Arrhenius Concept
This theory only applies to aqueous solutions and cannot explain the acidic or basic nature of compounds like CO₂ or NH₃, which don’t contain H⁺ or OH⁻ ions directly.
Bronsted-Lowry Concept
The Bronsted-Lowry concept, introduced in 1923, defines acids and bases based on proton transfer:
- Acid: A substance that donates a proton (H⁺)
- Base: A substance that accepts a proton (H⁺)
Conjugate Acid-Base Pairs
When an acid donates a proton, it forms a conjugate base. When a base accepts a proton, it forms a conjugate acid. For example, when HCl reacts with water, HCl acts as an acid and water acts as a base, forming H₃O⁺ (conjugate acid) and Cl⁻ (conjugate base).
Water as an Amphoteric Compound
Water can act as both an acid and a base depending on what it reacts with. This dual behavior is called amphoteric — a key concept frequently tested in 10th Class Chemistry Chapter 10 Notes-based exams.
Lewis Concept of Acids and Bases
The Lewis concept broadens the definition further:
- Lewis Acid: A substance that can accept a pair of electrons (e.g., BF₃, AlCl₃)
- Lewis Base: A substance that can donate a pair of electrons (e.g., NH₃)
The product of a Lewis acid-base reaction is called an adduct, formed through a coordinate covalent bond.
Chemical Properties of Acids
Acids show several characteristic reactions:
- Reaction with metals – produces salt and hydrogen gas
- Reaction with carbonates/bicarbonates – releases carbon dioxide gas
- Reaction with bases – forms salt and water (neutralization)
- Reaction with sulphites/bisulphites – releases sulphur dioxide gas
- Reaction with sulphides – releases hydrogen sulphide gas
Chemical Properties of Bases
Bases also have distinct reactions worth remembering:
- React with acids to form salt and water
- React with ammonium salts to release ammonia gas
- Precipitate insoluble hydroxides when added to heavy metal salt solutions
pH and pOH: Measuring Acidity
One of the most important numerical topics in 10th Class Chemistry Chapter 10 Notes is pH — the negative logarithm of hydrogen ion concentration.
pH = -log [H⁺]
Similarly, pOH is the negative logarithm of hydroxide ion concentration:
pOH = -log [OH⁻]
At 25°C, the relationship between the two is always:
pH + pOH = 14
Understanding the pH Scale
- pH less than 7 → Acidic solution
- pH equal to 7 → Neutral solution
- pH greater than 7 → Basic solution
The pH scale is logarithmic, meaning a solution with pH 1 is ten times more acidic than one with pH 2.
Indicators and Their Uses
Indicators are organic compounds that change color in acidic and basic solutions.
| Indicator | Acidic Color | Basic Color |
|---|---|---|
| Litmus | Red | Blue |
| Phenolphthalein | Colorless | Pink/Red |
| Methyl Orange | Red | Yellow |
A universal indicator is a mixture of different indicators used to measure the exact pH of a solution by comparing the resulting color to a standard chart.
Salts: Types and Preparation
Salts are ionic compounds formed by the neutralization of an acid with a base. According to 10th Class Chemistry Chapter 10 Notes, salts are classified into six main types:
- Normal (Neutral) Salts – e.g., NaCl
- Acidic Salts – e.g., KHSO₄
- Basic Salts – e.g., Al(OH)₂Cl
- Double Salts – e.g., Mohr’s salt
- Mixed Salts – e.g., bleaching powder
- Complex Salts – e.g., K₄[Fe(CN)₆]
Methods for Preparing Soluble Salts
- Reaction of an acid with a metal
- Reaction of an acid with a base (neutralization)
- Reaction of an acid with a metallic oxide
- Reaction of an acid with a carbonate
Insoluble salts, on the other hand, are prepared by mixing two soluble salt solutions so that one product precipitates out.
Uses of Acids, Bases, and Salts
Understanding real-life applications makes these 10th Class Chemistry Chapter 10 Notes easier to remember:
- Sulphuric acid – used in fertilizers and batteries
- Sodium hydroxide – used in soap and paper manufacturing
- Sodium chloride – common table salt, also used for de-icing roads
- Calcium sulphate – used to prepare plaster of Paris
Stomach Acidity and Its Prevention
The stomach naturally produces hydrochloric acid to digest food, but excess acid causes hyperacidity, which can lead to heartburn. Prevention includes avoiding overeating, eating on time, and staying upright after meals — a practical, exam-relevant topic within this chapter.
Quick Revision Points
- Arrhenius, Bronsted-Lowry, and Lewis concepts each define acids/bases differently.
- Water is amphoteric — it can act as both acid and base.
- pH + pOH always equals 14 at 25°C.
- Indicators change color at specific pH values.
- Salts are classified into six types based on formation and composition.
These 10th Class Chemistry Chapter 10 Notes give a complete, exam-ready summary of the chapter for quick revision.
FAQs
Q1. What is Chapter 10 of 10th Class Chemistry about?
Chapter 10 covers Acids, Bases and Salts, explaining the Arrhenius, Bronsted-Lowry, and Lewis concepts, along with pH, indicators, and the classification and preparation of salts.
Q2. What is the formula for pH?
pH is calculated as the negative logarithm of hydrogen ion concentration: pH = -log [H⁺]. It tells us whether a solution is acidic, neutral, or basic on a scale from 0 to 14.
Q3. Why are 10th Class Chemistry Chapter 10 Notes important for exams?
These notes simplify complex theories, numerical formulas, and salt classifications into easy points, helping students prepare quickly for both objective and subjective exam sections.
Q4. What is the difference between Arrhenius and Bronsted-Lowry acids?
Arrhenius acids release H⁺ ions only in water, while Bronsted-Lowry acids donate a proton to any substance, even in non-aqueous conditions. This makes the Bronsted-Lowry concept broader and more widely applicable.
Q5. What is an amphoteric substance?
An amphoteric substance can act as both an acid and a base, depending on the reaction. Water is the most common example, acting as a base with HCl and as an acid with ammonia.
Q6. What are the main types of salts?
The six main types of salts are normal, acidic, basic, double, mixed, and complex salts. Each type is classified based on how the acid and base react during neutralization.