---
type: "Chapter"
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entity_type: "chapter"
id: "69bff410fb5daab696d9b642"
title: "Exploring Substances: Acidic, Basic, and Neutral"
board: "CBSE"
curriculum: "CBSE"
class: "Class 7"
subject: "Science"
book: "Curiosity"
chapter: "Exploring Substances: Acidic, Basic, and Neutral"
chapter_slug: "exploring-substances-acidic-basic-and-neutral"
canonical_url: "https://www.edzy.ai/cbse-class-7-science-curiosity-exploring-substances-acidic-basic-and-neutral"
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source: "Edzy"
version: 1
last_updated: "2026-06-20"
---

# Exploring Substances: Acidic, Basic, and Neutral

On 28 February, Ashwin and Keerthi participated in a science fair that showcased various science activities related to acids, bases, and neutral substances. Their curiosity led them to explore the color changes that occurred when different substances were mixed, enhancing their understanding of the properties of substances in nature.

---

## Knowledge Snapshot

| Field | Details |
| :--- | :--- |
| Class | Class 7 |
| Subject | Science |
| Book | Curiosity |
| Chapter | Exploring Substances: Acidic, Basic, and Neutral |
| Pages | 7-22 |

---

## Chapter Summary

### Short Summary
This chapter introduces students to acids, bases, and neutral substances through experiments that demonstrate how different indicators react to these substances.

### Detailed Summary
The chapter begins with Ashwin and Keerthi's exploration at a science fair on National Science Day, where they learn how substances can show color changes based on their acidic or basic nature. The siblings engage in activities like testing various liquids with litmus paper to observe reactions. The chapter also explains how to prepare lime water and distinguishes it from other substances, enriching their overall understanding of the chemical nature of substances around them.

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## Topic-Wise Explanation

### Nature – Our Science Laboratory
The chapter starts with an introduction to the exploration of substances and their classifications as acidic, basic, or neutral.

### Litmus as an Indicator
The activity involves using blue and red litmus paper to test various substances such as lemon juice, vinegar, and baking soda to observe color changes and determine their acidic or basic properties.

### Red Rose as an Indicator
*Omitted; context does not provide information on this topic.*

### Turmeric as an Indicator
*Omitted; context does not provide information on this topic.*

### What Happens When Acidic Substances Mix with Basic Substances?
The chapter discusses the reactions observed in indicators when acidic substances mix with basic solutions, leading to various color reactions.

### Neutralisation in Daily Life
*Omitted; context does not provide information on this topic.*

---

## Character Analysis
*Omitted; the chapter does not contain characters beyond Ashwin and Keerthi as participants.*

---

## Core Ideas

| Idea | Explanation |
| :--- | :--- |
| Acids and Bases | The fundamental classification of substances based on their pH levels and reactions with indicators. |

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## Key Concepts

| Concept | Meaning |
| :--- | :--- |
| Litmus | A natural dye that changes color to indicate the acidity or basicity of a solution. |

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## Important Points for Revision

* The science fair demonstrates practical applications of scientific concepts.
* Observing color changes in substances helps classify them as acidic or basic.
* Litmus paper is a key indicator used in these experiments.
* Lime water is prepared by mixing calcium oxide with water and filtering it.
* The distinction between acids and bases is critical in understanding their interactions.
* Various household substances can act as acids or bases.
* The importance of indicators in identifying the chemical nature of solutions.
* Experimental observation is key to learning in science.

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## Vocabulary and Glossary

| Word / Phrase | Meaning |
| :--- | :--- |
| Lime Water | A solution of calcium hydroxide in water, used to identify carbon dioxide through turbidity. |

---

## Practice Questions

### Short Answer Questions
1. What colors do blue and red litmus paper change to when introduced to acidic solutions?
2. How can lime water be prepared?
3. What is the significance of using indicators in chemistry?
4. Name two acidic substances mentioned in the chapter.
5. Explain the role of the science fair for Ashwin and Keerthi.

### Long Answer Questions
1. Describe the activities Ashwin and Keerthi participated in at the science fair and the observations they made.
2. Discuss how litmus works as an indicator and the scientific principle behind its color change.
3. Explain the importance of studying acids and bases in everyday life.

---

## Related Concepts
* Indicators
* Acid-base reactions
* Neutral solutions

---

## Source Attribution

| Field | Value |
| :--- | :--- |
| Source | Edzy |
| Reference Type | examSubjectBookChapter |
| Reference ID | 69bff410fb5daab696d9b642 |
| Canonical URL | https://www.edzy.ai/cbse-class-7-science-curiosity-exploring-substances-acidic-basic-and-neutral |
| Markdown URL | https://www.edzy.ai/okf/chapter/cbse-class-7-science-curiosity-exploring-substances-acidic-basic-and-neutral.md |