---
title: "NCERT Solutions for Class 7 Science Chapter 2 Exercise 2.5"
url: https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions/exercise-2-5
dateModified: 2026-10-07T16:06:22+00:00
---

# NCERT Solutions for Class 7 Science Chapter 2 Exercise 2.5

Chapter 2: Exploring Substances: Acidic, Basic, and Neutral. Every question from Exercise 2.5, 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 2.5: Let us prepare

### Question 1

*Activity*

Record your observations in Table 2.4.

**Solution**

1. Turmeric paper turns red when tested with basic substances like soap solution, baking soda solution, and lime water.
2. Turmeric paper shows no change in colour and remains yellow when tested with acidic substances (like lemon juice, vinegar) and neutral substances (like water, salt solution).

**Answer:** Turmeric paper turns red with basic solutions and remains yellow with acidic and neutral solutions.

> Common mistake: Assuming turmeric paper turns red with all substances.

### Question 2

*2 marks · Very short answer*

Do all samples change the colour of the turmeric paper?

**Solution**

1. No, all samples do not change the colour of the turmeric paper.
2. Turmeric paper changes its colour only when tested with basic substances, remaining unchanged with acidic and neutral substances.

**Answer:** No, only basic samples change the colour of the turmeric paper to red.

> Common mistake: Stating that all samples alter the indicator colour.

### Question 3

*3 marks · Short answer*

Group the samples which do not change the colour of the turmeric paper.

**Solution**

1. The samples which do not change the colour of the turmeric paper include both acidic substances (such as lemon juice, amla juice, tamarind water, and vinegar) and neutral substances (such as tap water, sugar solution, and salt solution).
2. Compared to Table 2.2, these comprise the samples belonging to Group A (acidic) and Group C (neutral).
3. This shows that turmeric paper can identify basic substances but cannot differentiate between acidic and neutral substances.

**Answer:** Acidic and neutral samples from Group A and Group C do not change the yellow colour of turmeric paper.

> Common mistake: Forgetting that neutral substances also fail to change turmeric paper colour.

## Related pages

- [All Chapter 2 NCERT solutions](https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions)
- [Exercise 2.1](https://www.swavid.com/science/class/7/chapter/exploring-substances-acidic-basic-and-neutral/ncert-solutions/exercise-2-1)
- [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 2.6](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