---
title: "NCERT Solutions for Class 7 Science Chapter 2 Exercise 2.1"
url: https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions/exercise-2-1
dateModified: 2026-10-07T16:06:22+00:00
---

# NCERT Solutions for Class 7 Science Chapter 2 Exercise 2.1

Chapter 2: Exploring Substances: Acidic, Basic, and Neutral. Every question from Exercise 2.1, with full working and the final answer.

Free PDF (16 pages): https://www.swavid.com/api/seo/pdf/ncert/science/class-7/swavid-ncert-solutions-class-7-science-chapter-2-exploring-substances-acidic-basic-and-neutral-13aedb74b7.pdf

## Activity 2.1: Let us explore

### Question 1

*Activity*

Do you observe any change in the colour of the blue litmus pieces?

**Solution**

1. Add a drop of each test sample onto pieces of blue litmus paper placed on a clean and dry white tile.
2. Observe that acidic samples turn blue litmus paper red, while basic and neutral samples do not change its blue colour.

**Answer:** Acidic samples turn blue litmus paper red, whereas basic and neutral samples show no colour change.

### Question 2

*Activity*

Record your observations in Table 2.1.

**Solution**

1. Test each sample from the given list using both blue and red litmus papers.
2. Record the observed colour changes for each sample systematically in Table 2.1.

**Answer:** Observations of colour changes for all tested samples are recorded in Table 2.1.

### Question 3

*Activity*

Repeat the same activity with pieces of red litmus paper as shown in Fig. 2.2b and record your observations in Table 2.1.

**Solution**

1. Add a drop of each test sample onto pieces of red litmus paper placed on a clean and dry white tile.
2. Observe that basic samples turn red litmus paper blue, while acidic and neutral samples show no colour change.

**Answer:** Basic samples turn red litmus paper blue, whereas acidic and neutral samples show no colour change.

## Related pages

- [All Chapter 2 NCERT solutions](https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions)
- [Exercise 2.2](https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions/exercise-2-2)
- [Exercise 2.4](https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions/exercise-2-4)
- [Exercise 2.5](https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions/exercise-2-5)
- [Exercise 2.6](https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions/exercise-2-6)
- [Exercise 2.7](https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions/exercise-2-7)

Solutions written by SwaVid, a personal AI tutor for Class 6 to 10 Maths and Science. Practise this chapter free: https://www.swavid.com/start/student