NCERT Solutions for Curiosity Chapter 2 Exploring Substances: Acidic, Basic, and Neutral
Updated on 2026-09-05
About this chapter
The chapter opens at a school science fair on National Science Day, where a sprayed liquid makes hidden writing appear on a white sheet of paper. The whole chapter is the explanation of that trick. Substances around us are of three kinds — acidic , basic and neutral . A substance that shows different colours in acidic and basic solutions is an acid-base indicator . Litmus , obtained from lichens , is the standard natural indicator. Acids turn blue litmus red ; bases turn red litmus blue ; neutral substances change neither. Red rose extract is another indicator — red in acid, green in base. Turmeric paper turns red only in a base, so it can spot bases but cannot tell an acid from a neutral substance. Acids taste sour (lemon, amla, tamarind, vinegar); bases feel soapy or slippery and general
- –9Section 2.1.1 Litmus as an indicator
- — What litmus is, and the Holistic Lens box
- — Taste, touch and the acids in food
- — Looking for other indicators
- Red rose as an indicator
- –13Section 2.1.2
- Fascinating Facts
- –15Section 2.1.3 Turmeric as an indicator
- — Onion as an olfactory indicator
- –21End-of-chapter questions
Exercises
- –9Section 2.1.1 Litmus as an indicator — Activity 2.1: Let us explore Page 8
- In-text Questions — — What litmus is, and the Holistic Lens box Page 10
- Activity 2.2: Let us relate and explore — — Taste, touch and the acids in food Page 11
- In-text Questions — — Looking for other indicators Page 11
- Activity 2.3: Let us prepare — Red rose as an indicator Page 12
- –13Section 2.1.2 — Activity 2.4: Let us find out Page 12
- Fascinating Facts — In-text Questions Page 14
- –15Section 2.1.3 Turmeric as an indicator — Activity 2.5: Let us prepare Page 14
- –16Fascinating Facts, the Guru Purnima greeting card and olfactory indicators — In-text Questions Page 15
- Activity 2.6: Let us investigate — — Onion as an olfactory indicator Page 16
- Activity 2.7: Let us experiment — What Happens When Acidic Substances Mix with Basic Substances? Page 17
- –19Section 2.3 Neutralisation in Daily Life, and Let us wrap up! — In-text Questions Page 18
- –21End-of-chapter questions — Let Us Enhance Our Learning Page 20
- Thinking beyond the chapter — Dive Deeper Page 22
- Projects and further exploration — Exploratory Projects Page 22