| Board | CBSE |
| Useful for | Class 10 Students |
| Subject | Science |
| Chapter | Chapter 2 Acids Bases and Salts |
| Question Type | Assertion and Reason Questions |
| No. of Questions | 30 |
| With Answers | Yes |
| Important Link | Class 10 Science Chapterwise Assertion Reason |
Table of Contents
Assertion and Reason Questions for Class 10 Science Chapter 2 Acids, Bases and Salts
Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Q.1. Assertion (A) : The acid must always be added to water with constant stirring.
Reason (R) : Mixing of an acid with water decreases the concentration of H+ ions per unit volume.
Answer
(b)Q.2. Assertion (A) : Copper sulphate crystals are wet because it contains water of crystallisation.
Reason (R) : Water of crystallisation is the fixed number of molecules of water present in one
formula unit of salt.
Answer
(d) The Assertion is false. Copper sulphate is not wet. It is an hydrated salt, as it contains water molecules.Q.3. Assertion (A) : The aqueous solutions of glucose and alcohol do not show acidic character.
Reason (R) : Aqueous solutions of glucose and alcohol do not give H+ ions.
Answer
(a)Q.4. Assertion (A) : HCl gas does not change the colour of dry blue litmus paper.
Reason (R) : HCl gas dissolves in the water present in wet litmus paper to form H+ ions.
Answer
(a)Q.5. Assertion (A) : Weak acids have low electrical conductivity.
Reason (R) : Strong acids and weak acids have equal concentration of hydrogen ions in their solutions.
Answer
(c)Also read: Case Study Questions for Class 10 Science Chapter 2 Acids, Bases and Salts
Q.6. Assertion (A): Pure water is neither acidic nor basic.
Reason (R) : The pH of a solution is inversely proportional to the concentration of hydrogen
ions in it.
Answer
(b)Q.7. Assertion (A) : During electrolysis of concentrated aqueous solution of sodium chloride, hydrogen is produced at anode and chlorine gas is produced at cathode.
Reason (R) : Ions get attracted to oppositely charged electrodes.
Answer
(d)Q.8. Assertion (A) : Baking powder is used in making cake instead of using only baking soda.
Reason (R) : Baking powder contains tartaric acid which reacts with sodium carbonate and removes bitter taste.
Answer
(a)Q.9. Assertion (A) : The chemical formula of bleaching powder is CaOCI.
Reason (R) : Calcium oxide reacts with chlorine to form bleaching powder.
Answer
(c)Q.10. Assertion (A): Plaster of Paris is stored in a moisture proof container.
Reason (R) : Plaster of Paris sets into a hard mass on wetting with water to form anhydrous calcium sulphate.
Answer
(c)Q.11. Assertion (A): The chemical name of bleaching powder is calcium oxychloride.
Reason (R): Bleaching powder is used as an oxidising agent in chemical industries.
Answer
Answer: (b)Q.12. Assertion: The process of dissolving an acid or a base in water is highly exothermic reaction.
Reason: Water must always be added slowly to acid with constant stirring.
Answer
Answer: (c) The process of dissolving an acid or a base in water is highly exothermic reaction. Acid must always be added slowly to water with constant stirring.Q.13. Assertion : Phenolphthalein is an acid-base indicator.
Reason: Phenolphthalein gives different colours in acidic and basic medium.
Answer
Answer: (a)Q.14. Assertion: Calcium sulphate hemihydrate, CaSO4.1/2 H20 is called plaster of Paris.
Reason: Plaster of Paris is used for producing moulds for pottery and ceramics and casts of statues.
Answer
Answer: (b)Q.15. Assertion : pH = 7 signifies pure water.
Reason: pH of acetic acid is greater than 7.
Answer
Answer: (c) pH of acetic acid is less than 7.Q.16. Assertion : HCl is a stronger acid than acetic acid.
Reason: On dissociation, HCl yields lesser hydrogen ions for the same concentration as compared to acetic
acid.
Answer
Answer: (c) On dissociation, HCl yields more hydrogen ions for the same concentration as compared to acetic acid.Q.17. Assertion : pH of ammonium nitrate solution is acidic.
Reason: Solution of a salt of weak base and strong acid is acidic.
Answer
Answer: (a) Ammonium nitrate is a salt of ammonium hydroxide (weak base) and nitric acid (strong acid).Q.18. Assertion : Phosphoric acid is a weak acid.
Reason : Phosphoric acid when dissolved in water dissociates partially and produces very little H* ions.
Answer
Answer: (a)Q.19. Assertion : Antacids neutralize the effect of extra acid produced in the stomach during indigestion and thus provide relief.
Reason: Antacids are mild bases.
Answer
Answer: (a)Q.20. Assertion : Acetic acid does not act as an acid in benzene solution.
Reason: Benzene is non-polar.
Answer
Answer: (a) For ionization of an acid, polar solvents (like water) are required. As ionization does not take place in non-polar solvents (like benzene) so acetic acid does not acts as an acid.Q.21. Assertion : Bleaching powder reacts with dilute acids to evolve chlorine.
Reason: The chlorine liberated by the action of dilute acids on bleaching powder is called available chlorine.
Answer
Answer: (b)Q.22. Assertion : Sodium carbonate pentahydrate is also known as washing soda.
Reason: Chief raw materials for the manufacture of washing soda are NH3, NaCl and CaCO3.
Answer
Answer: (d)Q.23. Assertion: Common salt is used for the preparation of many chemicals such as sodium hydroxide, bleaching powder, baking soda, washing soda etc.
Reason : Main source of sodium chloride is sea water.
Answer
Answer: (b)Q.24. Assertion : AlCl3 is a basic salt.
Reason: AlCl3 is a salt of strong acid and a weak base.
Answer
Answer: (d)Q.25. Assertion : Baking soda is prepared by chlor-alkali process.
Reason: Brine decomposes to sodium hydroxide on passing electricity through it.
Answer
Answer: (d)Q.26. Assertion : Salt of KNO3 is formed by strong base and weak acid.
Reason: Salt of NH4Cl is formed by weak base and strong acid.
Answer
Answer: (d)Q.27. Assertion : Strength of the acid or base decreases with dilution.
Reason: Ionization of an acid or a base increases with dilution.
Answer
Answer: (b)Q.28. Assertion : Higher the H ion concentration, lower is the pH value.
Reason: The pH of a neutral solution=7, that of a basic solution < 7 and that of an acidic solution > 7.
Answer
Answer: (c)Q.29. Assertion : CH3COOH is used as vinegar in cooking and food preservatives.
Reason: Strong acids are those acids which ionise almost completely in aqueous solution and hence produce a large amount of Hions.
Answer
Answer: (b)Q.30. Assertion : Tooth decay starts when the pH of the mouth is lower than 5.5.
Reason: Enamel starts corroding below 5.5 pH.
Answer
Answer: (a)Related Posts
Frequently Asked Questions (FAQs) on Acids, Bases and Salts Assertion Reason Questions
A1: The best website for practicing assertion reason questions for class 10 science is physicsgurukul.com
A2: Yes, we have provided many questions in each chapter. So it is sufficient for practice.
A3: Assertion reason questions consists of two statements – Assertion and Reason
Assertion (A): This is a statement that could be a fact, an observation, or a conclusion.
Reason (R): This explains why the assertion is true (or false).
You need to analyze both statements and determine the relationship between them.
A4: Here are some tips for effective answering the assertion and reason questions.
1. Read both the Assertion and Reason carefully.
2. Think logically about the scientific concept involved.
3. Even if the Assertion sounds familiar, analyze it with the Reason provided.
4. Don’t be fooled by a partially true Reason.
5. Practice with sample questions from your textbook or other resources.
A5: Yes, Physics Gurukul provides assertion reason questions for all subjects. Click here to access assertion reason questions for all classes and subjects.
A6: Acids are substances that release hydrogen ions (H⁺) when dissolved in water. They have a sour taste, turn blue litmus paper red, and have pH values less than 7.
A7: Common acids include hydrochloric acid (HCl) found in gastric juice, citric acid found in citrus fruits like lemons and oranges, acetic acid found in vinegar, and sulfuric acid used in car batteries.
A8: Bases are substances that release hydroxide ions (OH⁻) when dissolved in water. They have a bitter taste, feel slippery to the touch, turn red litmus paper blue, and have pH values greater than 7.
A8: Common bases include sodium hydroxide (NaOH) used in drain cleaners and soap making, potassium hydroxide (KOH) used in fertilizers and industrial processes, and calcium hydroxide [Ca (OH)₂] used in cement and agriculture.
A10: The pH scale is a measure of the acidity or basicity of a solution. It ranges from 0 to 14, where 7 is considered neutral, values below 7 indicate acidity, and values above 7 indicate alkalinity.
A11: Neutralization is a chemical reaction between an acid and a base to form salt and water. In this reaction, the H⁺ ions from the acid combine with the OH⁻ ions from the base to form water, while the remaining ions form the salt.
A12: Antacid tablets contain basic substances like magnesium hydroxide or calcium carbonate. When these tablets are consumed, they react with the excess acid in the stomach, neutralizing it and providing relief from acidity.
A13: pH plays a crucial role in various everyday processes, such as digestion in the human body, water treatment, agriculture (soil pH affects plant growth), and the manufacturing of various products like cosmetics and food items.
A14: The pH of a solution can be determined using pH indicators, pH paper/strips, or pH meters. pH indicators change color depending on the acidity or basicity of the solution, while pH paper/strips provide a numerical pH value, and pH meters directly measure pH electronically.
A15: Acid rain, which is formed when sulfur dioxide and nitrogen oxides react with water in the atmosphere, can lead to the acidification of water bodies, soil degradation, damage to vegetation, and corrosion of buildings and monuments.
are these correct
Yes, but if any answer is wrong. Then pl report. We will make necessary corrections.
yes thats all right except one i.e. formula of bleaching powder is give caocl but it is caocl2.
The second answer is wrong
Assertion is wrong. Copper sulphate is not wet. It is an hydrated salt, as it contains water molecules.
Assertion is false and Reason is true.
Answer of Q 4 is wrong the answer should be option b
The reason doesn’t satisfy the assertion
It makes me happy for my preparation for preboards
Please give explanation of these assertions and reasons questions.