Class 7 Science — Chapter 2: Exploring Substances: Acidic, Basic, and Neutral
Chapter 2: Exploring Substances: Acidic, Basic, and Neutral is a chapter in Class 7 Science (Curiosity), part of the CBSE NCERT curriculum followed by over 25 million students across India. This chapter covers 8 topics including Acid-Base Indicators, Litmus as a Natural Indicator, Identifying Acidic Substances. BrainWeave provides free AI-powered explanations — by voice or text, in Hindi or English — with no signup required.
What you'll learn
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▸Acid-Base IndicatorsCore conceptindicatoracid-base indicatornatural indicatorsynthetic indicator
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▸Litmus as a Natural IndicatorCore conceptlitmuslitmus paperlichensnatural indicator
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▸Identifying Acidic SubstancesCore conceptacidicacidblue litmussourlemon juice
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▸Identifying Basic SubstancesCore conceptbasicbasered litmussoapysoap solution
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▸Neutral SubstancesCore conceptneutrallitmus testno changesalt solutionsugar solution
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▸Common Acids in Edible Substancescitric acidascorbic acidtartaric acidvinegarcurd
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▸Preparing and Using Other Natural Indicatorsred roseturmericbeetrootextracthomemade indicator
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▸Application of Acidity/Basicity in Soilhydrangeasoilacidic soilbasic soilpH application
Chapter Summary
Understand that indicators are special substances used to test whether a substance is acidic or basic. They change color when added to an acid or a base.
Learn that litmus is a natural dye extracted from lichens and is the most common indicator. It is available as a solution or as paper strips (red and blue litmus paper).
Understand that acidic substances are those that turn blue litmus paper to red. They are typically sour in taste.
Understand that basic substances are those that turn red litmus paper to blue. They are typically bitter in taste and feel soapy to the touch.
Learn that substances that do not change the color of either red or blue litmus paper are called neutral substances. They are neither acidic nor basic.
Recognize the names of common acids present in everyday food items, such as citric acid in lemons, ascorbic acid in amla, and tartaric acid in tamarind.
Understand that indicators can be prepared from natural materials like red rose petals, turmeric, or beetroot. For example, red rose extract turns red in acidic solutions and green in basic solutions.
Understand the real-world application of how the acidic or basic nature of soil can affect plant characteristics, such as the flower color of the Hydrangea plant.
Practice Questions from this Chapter
Tap "Get Solution" on any question to ask our AI tutor.
- Show other natural indicators. Get Solution →
- Explore common acids in everyday foods. Get Solution →
- Discover surprising uses for bases. Get Solution →
- What is the natural source of litmus, a common acid-base indicator? Get Solution →
- What color does blue litmus paper turn when an acidic substance is applied to it? Get Solution →
- According to the text, substances that turn red litmus paper to blue are classified as what? Get Solution →
- Substances like tap water or sugar solution, which do not change the color of either red or blue litmus paper, are described as being what? Get Solution →
- What is the characteristic taste of edible acidic substances like lemon juice and amla? Get Solution →
Did you know?
- 💡 Your stomach acid can dissolve metals, but a special lining keeps you safe.
- 💡 Slugs and snails produce a basic, slippery mucus to move around and protect themselves.
- 💡 The color of some flowers can change if the soil they grow in becomes more acidic or basic.
- 💡 Ancient Egyptians used vinegar, an acid, to clean and preserve objects thousands of years ago.
- 💡 Some fish can sense tiny changes in water's acidity and move to find the perfect neutral spot.
Frequently Asked Questions
How many topics are covered in this chapter?
This chapter covers 8 key topics: Acid-Base Indicators, Litmus as a Natural Indicator, Identifying Acidic Substances, Identifying Basic Substances, Neutral Substances, and more. The BrainWeave AI tutor explains each one with examples.
Is Chapter 2: Exploring Substances: Acidic, Basic, and Neutral important for board exams?
Class 7 is a foundation year. Mastering this chapter now will help you build strong fundamentals for the higher classes.
Can I get NCERT solutions for this chapter in Hindi?
Yes. BrainWeave's AI tutor supports Hindi, English, and Hinglish for both voice and text chat. Just ask your question in your preferred language.
Is BrainWeave free for Class 7?
Yes. BrainWeave's free Spark plan gives generous daily messages — enough for regular homework. Premium features unlock when you bring your own free Google Gemini API key.
Can I use voice chat for this chapter?
Absolutely. Tap the mic, ask any question about Chapter 2: Exploring Substances: Acidic, Basic, and Neutral, and the AI tutor will explain it back in voice and text.
How is BrainWeave better than static NCERT solutions sites?
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