CBSE · Class 10 · Science · Chapter 2
Acids, Bases and Salts — Class 10 Science (CBSE) explained
- Board exam 2026-27
- 4 lessons
- 30 scenes
- About 23 min
- Updated
Quick answer
Acids, Bases and Salts is Chapter 2 of CBSE Class 10 Science. It covers indicator evidence, Neutralisation: acid and base form salt and water, hydroxide ions and alkalis, acid and base strength, sources and importance of common salt and bleaching powder. AI Lessons teaches it in 4 narrated lessons (about 23 minutes) with an AI tutor and board-pattern practice.
What you’ll learn
Lesson 1: Recognising Acids and Bases, and Following Their Reactions
6 min- Recognise Acids and Bases Without Tasting
- Colour Indicators and Olfactory Indicators
- Acid and Metal: Recognising Hydrogen
- Sodium Hydroxide Reacts with Zinc
- Two Salts, One Reaction Pattern
- Why Lime Water Turns Milky, Then Clears
- Neutralisation: Acid and Base Form Salt and Water
- Recognise Basic and Acidic Oxide Behaviour
Lesson 2: Ions, Water and the pH Scale
5 min- Hydrogen in a Formula Does Not Automatically Make an Acid
- Water Enables Acidic Behaviour
- Hydroxide Ions, Alkalis and the Ionic View of Neutralisation
- Dilution Releases Heat: Understand the Safety Rule
- Read the pH Scale
- Equal Concentration Does Not Mean Equal Acid Strength
- Living Systems Need Suitable pH Ranges
Lesson 3: Everyday pH and the Chemistry of Salts
5 min- Excess Acid, Antacids and Tooth Decay
- Naturally Occurring Acids and Chemical Defence
- Salts Belong to Families Through Shared Ions
- Not Every Salt Solution Is Neutral
- Common Salt: Food, Deposits and Chemical Raw Material
- The Chlor-Alkali Process Produces Three Useful Chemicals
- Bleaching Powder: Manufacture and Uses
Lesson 4: Useful Salts, Crystal Water and Chapter Practice
6 min- Baking Soda Is Sodium Hydrogencarbonate
- Why Baking Powder Makes Cakes Rise
- Washing Soda: A Useful Hydrated Salt
- Apparently Dry Crystals Can Contain Water
- Plaster of Paris Changes Back into Gypsum
- The Group Activity: Prepare and Compare a Natural Indicator
- The Group Activity: A Soda-Acid Fire Extinguisher
- Chapter Recap: Explain, Predict and Practise
Key concepts
- Indicator evidence
- Litmus is a natural indicator extracted from lichen, and its solution is purple when neither acidic nor basic.
- Neutralisation: acid and base form salt and water
- A reaction between an acid and a base that gives salt and water is called a neutralisation reaction.
- Hydroxide ions and alkalis
- A base that dissolves in water is called an alkali. Not all bases dissolve in water, so the words base and alkali are not identical in meaning.
- Acid and base strength
- Acids that produce more hydrogen ions are called strong acids.
- Sources and importance of common salt
- Large crystals may look brown because of impurities; this material is called rock salt. Its beds formed when ancient seas dried up, and it is mined like coal.
- Bleaching powder
- Chlorine from the chlor alkali process is used to manufacture bleaching powder. In an industrial animation, chlorine acts on dry slaked lime, which is calcium hydroxide.
- Baking soda identity and heating
- Sodium hydrogencarbonate and sodium carbonate are different compounds, not two names for the same substance.
- Baking powder and gas production
- Baking powder is a mixture of baking soda and tartaric acid, a weak edible acid.
Exam focus
- Board exam
- CBSE assesses this chapter in the 2026-27 year-end board examination.
- Syllabus
- Acids, Bases and Salts: Acids and Bases - definitions in terms of furnishing of H+ and OH- ions, identification using indicators, chemical properties, examples and uses, neutralization, concept of pH scale (Definition relating to logarithm not required), importance of pH in everyday life; preparation and uses of Sodium Hydroxide, Bleaching Powder, Baking soda, Washing soda and Plaster of Paris.
- Exam note
- pH: the definition relating to logarithm is not required.
- Paper pattern
- 80 marks, 3 hours, 39 questions in three sections (A Biology, B Chemistry, C Physics); internal assessment 20. Units: I Chemical Substances 25, II World of Living 25, III Natural Phenomena 12, IV Effects of Current 13, V Natural Resources 5.
- Question style
- About 50% of board questions are competency-focused: case-based, source-based, integrated, data interpretation, situational and application-oriented.
- Practice in the app
- 93 board-pattern questions with marking schemes: 33 multiple choice (1 mark), 14 assertion–reason (1 mark), 18 very short answer (2 marks), 15 short answer (3 marks), 4 long answer (5 marks) and 9 case-based (4 marks).
Sample questions with marking points
Board-pattern questions from the AI Lessons practice set for this chapter. The marking points show what an examiner looks for; full model answers are in the app.
Very short answer2 marks
In the chemical explanation of relief from a bee sting, baking soda is preferred to vinegar. Explain why and name the acid present in vinegar.
Marking points
- Baking soda is a mild base.0.5
- It neutralises the acid left by the bee sting.0.5
- Vinegar is acidic and therefore does not neutralise the sting acid.0.5
- The acid in vinegar is acetic acid.0.5
Short answer3 marks
A product label claims that sodium hydrogencarbonate is useful only in food preparation. Evaluate this claim by explaining its chemical role in baking powder and in antacids. Name the acid present in baking powder.
Marking points
- Names tartaric acid as the acid in baking powder.0.5
- States that sodium hydrogencarbonate reacts with the acid in baking powder.0.5
- Carbon dioxide released makes bread or cake rise and become soft and spongy.1
- Its alkaline nature enables it to neutralise excess stomach acid as an antacid ingredient.1
Frequently asked questions
What does Acids, Bases and Salts cover in Class 10 Science?
It covers indicator evidence, Neutralisation: acid and base form salt and water, hydroxide ions and alkalis, acid and base strength, sources and importance of common salt and bleaching powder. AI Lessons teaches it in 4 lessons: Recognising Acids and Bases, and Following Their Reactions, Ions, Water and the pH Scale, Everyday pH and the Chemistry of Salts and Useful Salts, Crystal Water and Chapter Practice.
Is Acids, Bases and Salts in the CBSE Class 10 board exam?
Yes. CBSE assesses Acids, Bases and Salts in the 2026-27 year-end board examination.
Without tasting any laboratory substance, which description of the characteristic tastes of acids and bases is correct?
Acids are sour; bases are bitter. Acids have a characteristic sour taste, while bases have a characteristic bitter taste; these properties are not reversed or shared by both.
What is a neutralisation reaction?
A reaction between an acid and a base that gives salt and water is called a neutralisation reaction.
What is an alkali?
A base that dissolves in water is called an alkali. Not all bases dissolve in water, so the words base and alkali are not identical in meaning.
What are strong acids?
Acids that produce more hydrogen ions are called strong acids.
At the same concentration, which criterion identifies the stronger base?
It produces more OH^- ions in water. Base strength depends on the hydroxide ions produced in water; a stronger base produces more at the same concentration.
How does AI Lessons teach Acids, Bases and Salts?
As 4 narrated, animated lessons (30 scenes, about 23 minutes in all), with an AI tutor that knows the step you are on and board-pattern practice with marking schemes. The full lessons open after sign-in on an AI Lessons account.
Watch the full lesson
Acids, Bases and Salts, as a narrated, animated lesson
4 lessons · 30 animated scenes · about 23 minutes, with an AI tutor that knows the step you are on and 93 board-pattern questions with marking schemes.
Lessons open after sign-in. A parent or guardian holds the account and adds each child.