Last Updated on May 7, 2025 by XAM CONTENT
Understanding the key concepts of Class 7 Science Chapter 2 – Exploring Substances: Acidic, Basic, and Neutral is crucial for exam success. To make your revision easier, we have created chapterwise mcq questions with Answers for class 7 Science based on the latest syllabus and exam pattern. It is a part of MCQ Questions for CBSE Class 7 Science Series.
These multiple-choice questions will help you assess your knowledge, improve accuracy, and boost confidence for your exams. Whether you are preparing for school tests, online tests or competitive exams, these Exploring Substances: Acidic, Basic, and Neutral MCQs will strengthen your conceptual clarity.
| Chapter | Exploring Substances: Acidic, Basic, and Neutral |
| Book | Curiosity |
| Type of Questions | MCQ Questions |
| Nature of Questions | Competency Based Questions |
| Board | CBSE |
| Class | 7 |
| Subject | Science |
| Useful for | Class 7 Studying Students |
| Answers provided | Yes |
| Difficulty level | Mentioned |
| Important Link | Class 7 Science Chapterwise MCQ Questions |
MCQ Questions on Exploring Substances: Acidic, Basic, and Neutral Class 7 Science – Curiosity
MCQs
Q1. Which of the following substances will turn blue litmus paper red?
(a) Soap solution
(b) Vinegar
(c) Baking soda solution
(d) Washing powder solution
Show Answer
Answer: (b)
Explanation: Acids like vinegar turn blue litmus paper red. Soap solution and baking soda are basic and turn red litmus blue.
Q2. What conclusion can you draw if a solution does not change the colour of either blue or red litmus paper?
(a) It is acidic
(b) It is basic
(c) It is neutral
(d) It is reactive
Show Answer
Answer: (c)
Explanation: Substances that do not affect the colour of either litmus paper are neutral in nature, such as sugar or salt solution.
Q3. Which natural indicator gives green colour in a basic solution?
(a) Litmus
(b) Turmeric
(c) Red rose extract
(d) Onion juice
Show Answer
Answer: (c)
Explanation: Red rose extract turns green in a basic solution and red in an acidic solution, making it a natural acid-base indicator.
Q4. What does turmeric paper indicate when it turns red upon adding a solution?
(a) The solution is acidic
(b) The solution is neutral
(c) The solution is basic
(d) The solution contains sugar
Show Answer
Answer: (c)
Explanation: Turmeric paper turns red in the presence of a basic solution but does not react to acidic or neutral substances.
Q5. Which of the following combinations results in a neutralisation reaction?
(a) Lemon juice and vinegar
(b) Vinegar and turmeric
(c) Lemon juice and lime water
(d) Soap solution and sugar solution
Show Answer
Answer: (c)
Explanation: Lemon juice (acid) and lime water (base) react to form salt and water, which is a neutralisation reaction.
Q6. Which of the following is an example of a natural indicator?
(a) Hydrochloric acid
(b) Phenolphthalein
(c) Turmeric
(d) Sodium hydroxide
Show Answer
Answer: (c)
Explanation: Turmeric is a natural indicator that changes colour in the presence of acids or bases.
Q7. Which of the following can act as an olfactory indicator?
(a) Onion juice
(b) Lemon juice
(c) Vinegar
(d) Salt water
Show Answer
Answer: (a)
Explanation: Olfactory indicators change or lose their smell in acidic or basic conditions. Onion juice is one such example.
Q8. What happens when an acid reacts with a base?
(a) Heat is absorbed
(b) Salt and water are formed
(c) Only water is formed
(d) Gas is always released
Show Answer
Answer: (b)
Explanation: An acid reacts with a base to form salt and water in a neutralisation reaction, often releasing heat.
Q9. Which of the following is true about neutral substances?
(a) They turn red litmus blue
(b) They turn blue litmus red
(c) They do not change the colour of litmus
(d) They are corrosive
Show Answer
Answer: (c)
Explanation: Neutral substances do not change the colour of red or blue litmus papers.
Q10. Which property is common to all acids?
(a) They taste bitter
(b) They turn blue litmus red
(c) They feel slippery
(d) They turn red litmus blue
Show Answer
Answer: (b)
Explanation: Acids turn blue litmus paper red. This is a universal property of acids.
Q11. Which solution would best neutralise a wasp sting (alkaline)?
(a) Soap solution
(b) Vinegar
(c) Baking soda
(d) Salt solution
Show Answer
Answer: (b)
Explanation: Wasp stings are alkaline and require an acidic substance like vinegar to neutralise the effect.
Q12. Which household substance is most likely to be basic?
(a) Lemon juice
(b) Vinegar
(c) Baking soda solution
(d) Apple juice
Show Answer
Answer: (c)
Explanation: Baking soda solution is basic in nature and turns red litmus blue.
Q13. Which of these indicators is synthetically prepared?
(a) Litmus
(b) Red cabbage juice
(c) Phenolphthalein
(d) Turmeric
Show Answer
Answer: (c)
Explanation: Phenolphthalein is a synthetic chemical indicator used in labs to detect acids and bases.
Q14. Which of the following can be used to treat soil that is too acidic?
(a) Adding vinegar
(b) Adding baking soda
(c) Adding quicklime
(d) Adding water
Show Answer
Answer: (c)
Explanation: Quicklime (a base) neutralises acidic soil and helps in better crop growth.
Q15. Which observation confirms a substance is acidic in nature?
(a) Turns red litmus blue
(b) No change in litmus colour
(c) Turns blue litmus red
(d) Smells sweet
Show Answer
Answer: (c)
Explanation: Turning blue litmus paper red confirms the substance is acidic.
Q16. What is the pH range of acidic substances?
(a) 7 to 14
(b) 0 to 7
(c) 7 only
(d) Above 7
Show Answer
Answer: (b)
Explanation: Acids have a pH below 7, with lower values being more strongly acidic.
Q17. What type of reaction is vinegar + baking soda?
(a) Endothermic reaction
(b) Displacement reaction
(c) Neutralisation reaction
(d) Physical reaction
Show Answer
Answer: (c)
Explanation: Vinegar (acid) and baking soda (base) undergo neutralisation to form salt, water, and carbon dioxide.
Q18. Which of the following indicators would lose smell in a basic solution?
(a) Red cabbage juice
(b) Onion juice
(c) Turmeric
(d) Litmus
Show Answer
Answer: (b)
Explanation: Onion juice is an olfactory indicator and loses its smell in basic conditions.
Q19. What happens to blue litmus in basic solution?
(a) It remains blue
(b) It turns red
(c) It turns green
(d) It disappears
Show Answer
Answer: (a)
Explanation: A basic solution does not affect blue litmus; it remains blue.
Q20. What is formed when an acid reacts with a base?
(a) Only water
(b) Salt and water
(c) Alcohol and water
(d) Acidic gas
Show Answer
Answer: (b)
Explanation: Neutralisation results in salt and water, and often releases heat as well.
We hope the given mcq questions with Answers for Exploring Substances: Acidic, Basic, and Neutral Class 7 helps you in your learning.
Quiz: Exploring Substances – Acidic, Basic, and Neutral
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Topics from which mcq questions may be asked
- Acids and bases
- Indicators
- Neutralization
Acids and bases are fundamental to chemistry and our daily life.
Frequently Asked Questions (FAQs) on Exploring Substances: Acidic, Basic, and Neutral MCQ Questions
Q1: Why should I practice Class 7 Science Chapter 2 MCQs?
A1: Practicing MCQs helps in quick revision, improves problem-solving speed, and enhances conceptual understanding of important topics in Class 7 Science.
Q2: Are these Class 7 Science MCQs based on the latest syllabus?
A2: Yes, all the MCQs are designed as per the latest CBSE syllabus and exam pattern to help students prepare effectively.
Q3: Where can I find more MCQs for Class 7 Science?
A3: You can find more chapter-wise MCQs on our website. These are designed to cover important concepts and prepare you for exams.
Q4: Are the answers provided for all MCQs?
A4: Yes, each MCQ is accompanied by the correct answer and explanations to help students understand and learn better.
Q5: How can I improve my performance in Class 7 Science MCQs?
A5: To improve your performance, practice regularly, revise key concepts, and take mock tests to assess your knowledge.
Q6: Do these MCQs help in school exams?
A6: Yes, these MCQs are aligned with school exam patterns and help in scoring well by strengthening conceptual clarity.
Q7: Can I download these MCQs for offline practice?
A7: Yes, you can download or print these MCQs for convenient offline practice.
