CBSE Class 10 Science • Chapter 2 • Revision 2026
Acids, Bases and Salts Class 10 Worksheet
Download the Acids, Bases and Salts Class 10 worksheet with answers PDF for CBSE Science self-study and revision. Practise MCQs with solutions, assertion–reason questions, case-based questions, and very short, short and long-answer questions covering indicators, pH, chemical reactions and important salts.
Why does moist blue litmus turn red in hydrogen chloride gas? How does baking powder make a cake rise? Why must Plaster of Paris be protected from moisture? Understanding the science behind these examples makes Acids, Bases and Salts Class 10 easier to revise and apply.
This Class 10 Science Acids, Bases and Salts worksheet gives you practice in recalling facts, interpreting observations and explaining reactions. Attempt the questions before checking solutions. Then revise the concept behind each mistake rather than memorising the answer alone.
Worksheet Question Types
- MCQs with solutions: Test indicators, formulas, pH and reaction products.
- Assertion and reason: Evaluate statements and the explanation linking them.
- Case-based questions: Interpret passages, observations and applications.
- Very short questions: Practise names, formulas and one-mark concepts.
- Short answers: Explain scientific reasons and balanced equations.
- Long-answer questions: Describe processes, preparations and uses.
Acids, Bases and Salts Class 10 Short Notes
In water, acids produce hydronium ions, H3O+, often represented as H+ in school equations. Bases such as sodium hydroxide produce hydroxide ions, OH−. A water-soluble base is called an alkali.
Acids turn blue litmus red, while bases turn red litmus blue. An acid reacting with a base commonly forms salt and water. The final solution’s pH depends on the reactants and their amounts; salt formation does not always mean the solution is neutral.
Indicators and pH: Important Points
| Indicator | Acidic Solution | Basic Solution |
|---|---|---|
| Litmus | Blue turns red. | Red turns blue. |
| Phenolphthalein | Colourless. | Pink in a suitably basic solution. |
| Methyl orange | Red when sufficiently acidic. | Yellow. |
| Turmeric | Remains yellow. | Reddish-brown. |
| Universal indicator | Colour varies with pH. | Colour varies with pH. |
For ordinary aqueous examples at about 25°C, pH below 7 is acidic, pH 7 is neutral and pH above 7 is basic. Lower pH means higher hydrogen-ion concentration. Each one-unit decrease in pH represents a tenfold increase in that concentration.
Worked Example: Compare pH 3 and pH 5
Both solutions are acidic.
Difference in pH = 5 − 3
= 2
Hydrogen-ion concentration ratio = 102
= 100.
The pH 3 solution has 100 times the hydrogen-ion concentration of the pH 5 solution.
Acid Strength and Concentration Are Different
Strength describes the extent of ionisation in water. Concentration describes the amount of acid in a given amount of solution. A strong acid can be dilute, and a weak acid can be concentrated.
Acids, Bases and Salts Class 10 Chemical Equations
Recognise the reaction pattern before learning an equation. Check formulas and balance each element on both sides.
-
Acid + suitable metal → salt + hydrogen:
Zn + 2HCl → ZnCl2 + H2 -
Acid + carbonate → salt + water + carbon dioxide:
Na2CO3 + 2HCl → 2NaCl + H2O + CO2 -
Acid + hydrogencarbonate → salt + water + carbon dioxide:
NaHCO3 + HCl → NaCl + H2O + CO2 -
Acid + base → salt + water:
HCl + NaOH → NaCl + H2O -
Acid + basic metal oxide → salt + water:
CuO + 2HCl → CuCl2 + H2O
Important Salts and Chemical Formulas
| Substance | Formula | Key Use or Fact |
|---|---|---|
| Common salt | NaCl | Raw material for important chemicals. |
| Baking soda | NaHCO3 | Used in baking powder. |
| Washing soda | Na2CO3·10H2O | Cleaning and removal of permanent water hardness. |
| Bleaching powder | CaOCl2 | School-level formula; bleaching and disinfection. |
| Plaster of Paris | CaSO4·½H2O | Casts and moulds. |
| Gypsum | CaSO4·2H2O | Used to prepare Plaster of Paris. |
Chlor-Alkali Process
Electrolysis of brine produces sodium hydroxide, chlorine and hydrogen:
2NaCl(aq) + 2H2O(l) → 2NaOH(aq) + Cl2(g) + H2(g)
Chlorine forms at the anode and hydrogen at the cathode. Sodium hydroxide remains in solution.
Heating Baking Soda
2NaHCO3 → Na2CO3 + H2O + CO2 , on heating.
Acids, Bases and Salts Class 10 MCQ with Answers
Which substance is sodium hydrogencarbonate?
A. Washing soda
B. Baking soda
C. Gypsum
D. Bleaching powder
Answer: B. Baking soda has formula NaHCO3.
Which solution is basic at about 25°C?
A. pH 2
B. pH 5
C. pH 7
D. pH 10
Answer: D. A pH above 7 indicates a basic solution.
Acids, Bases and Salts Class 10 Assertion and Reason
Assertion: Dry hydrogen chloride does not change dry blue litmus paper.
Reason: Water enables hydrogen chloride to form hydronium ions responsible for the acidic indicator response.
Answer: Both statements are true, and the reason correctly explains the assertion.
Evaluate each statement separately before checking whether the reason explains the assertion. Use the option codes printed in the question.
Acids, Bases and Salts Class 10 Case-Based Questions
Case Study: Carbon Dioxide and Limewater
Dilute hydrochloric acid reacts with sodium carbonate. The gas produced turns fresh limewater milky.
- Identify the gas.
- Write its formation equation.
- Explain the milkiness.
- Explain what excess gas may do.
Answers:
The gas is carbon dioxide.
Na2CO3 + 2HCl
→ 2NaCl + H2O + CO2.
CO2 + Ca(OH)2
→ CaCO3 + H2O.
Insoluble calcium carbonate causes milkiness.
Excess carbon dioxide can form soluble calcium hydrogencarbonate,
causing the milkiness to disappear.
Extra Questions, Activities and Scientific Reasons
Acids, Bases and Salts Class 10 competency-based questions ask you to explain observations and apply concepts. Practise these prompts alongside your worksheet:
- Explain why glucose solution does not show acidic behaviour despite containing hydrogen.
- Compare baking soda and baking powder.
- Explain the colour change when hydrated copper sulphate is heated.
- Describe water of crystallisation with an example.
- Explain the preparation and setting of Plaster of Paris.
- Describe the products and uses of the chlor-alkali process.
For activity-based answers, state the substance used, observation, inference and relevant equation. Match activity numbers with your prescribed textbook edition instead of relying on numbers alone.
HOTS Question: Are All Salt Solutions Neutral?
No. Sodium chloride solution is approximately neutral, ammonium chloride solution is acidic and sodium carbonate solution is basic. The nature of the ions formed in water determines the solution’s behaviour.
Use the Worksheet as a Chapter Test
Use the Acids, Bases and Salts Class 10 worksheet PDF as a practice test: attempt it in one sitting, then check the solutions. Review mistakes under formulas, reactions, pH and reasoning so you know what to revise.
Follow this with NCERT intext questions, exercise questions and relevant exemplar questions. Use verified previous year questions for additional practice. A chapter worksheet complements a full Science sample paper; it does not replace practice across the complete syllabus.
Notes, Mind Map and Related Worksheets
Review the Acids, Bases and Salts Class 10 notes and mind map to organise your revision.
Practise balancing with the Chemical Reactions and Equations worksheet with answers , or explore our CBSE Class 10 Science worksheets .
Frequently Asked Questions
What does the worksheet with answers PDF include?
It includes MCQs with solutions, assertion–reason questions, case-based questions, and very short, short and long-answer questions for chapter practice and self-checking.
Why does dry HCl not affect dry litmus?
Water is needed for hydrogen chloride to form hydronium ions that produce the acidic indicator response. Moist blue litmus turns red.
Why is glucose not an acid even though it contains hydrogen?
It does not produce hydronium ions in water in the way acids do. Hydrogen in a chemical formula alone does not establish acidic behaviour.
What is the difference between baking soda and washing soda?
Baking soda is NaHCO3. Washing soda is Na2CO3·10H2O. Their compositions and uses differ; they are not interchangeable names.
Why is tartaric acid added to baking powder?
It reacts with the alkaline material and helps prevent the bitter taste associated with sodium carbonate. Carbon dioxide released during the reactions helps the mixture rise.
What is water of crystallisation?
It is the fixed number of water molecules incorporated in a salt’s crystal structure. Copper sulphate pentahydrate, CuSO4·5H2O, is an example.
Why does copper sulphate turn white on heating?
Blue hydrated copper sulphate loses water of crystallisation and becomes white anhydrous copper sulphate. Adding water restores the blue hydrated form.
Why must Plaster of Paris be stored away from moisture?
It reacts with water to form gypsum and sets into a hard mass. A moisture-proof container prevents premature setting.
What does ½H2O mean in the Plaster of Paris formula?
It represents one water molecule for every two calcium sulphate formula units. It expresses a ratio, not a physically divided water molecule.
How does dilution change pH?
For ordinary textbook solutions, dilution moves an acid’s pH upwards towards neutral and a base’s pH downwards towards neutral by reducing ion concentration per unit volume.
Why should concentrated acid be added slowly to water?
Dilution releases heat. Slow addition with stirring allows heat to disperse. Adding water to concentrated acid can cause intense local heating and splashing.
How should I prepare important questions for 2026 revision?
Revise indicators, pH, formulas and reaction patterns. Practise MCQs, assertion–reason, case-based and written answers. Use your textbook, worksheet solutions and verified board questions to review weak areas.
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