Question 11
What change will you observe if you test soap with litmus paper (red and blue)?
Soap is alkaline/basic in nature. Hence, it will turn red litmus blue but no colour change will be observed with blue litmus paper.
Key Concepts Covered
This question tests your understanding of the following concepts from the chapter Carbon and its Compounds: Question, Change, Observe, Test, Soap, Litmus. These are fundamental topics in Science that students are expected to master as part of the CBSE Class 10 curriculum.
A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach This Question
Read the question carefully and identify what is being asked. Break down complex questions into smaller parts. Use the terminology and concepts discussed in this chapter. Structure your answer logically — begin with a definition or key statement, then provide supporting details. Review your answer to ensure it addresses all parts of the question completely.
Key Points to Remember
- Read the question carefully and identify all parts before answering.
- Use the terminology specific to this subject and chapter.
- Review the textbook content for this chapter before attempting questions.
- Practice writing concise, well-structured answers within time limits.
Practice more questions from Carbon and its Compounds — Science, Class 10 CBSE
Chapter 4: Carbon and Its Compounds — Quick Revision Guide
Introduction
Carbon is unique in its ability to form millions of compounds due to catenation and tetravalency. This chapter covers covalent bonding, hydrocarbons, homologous series, IUPAC nomenclature, and important carbon compounds.
Key Points at a Glance
- Carbon (2,4) forms 4 covalent bonds (sharing electrons) due to tetravalency
- Catenation: carbon-carbon bonding in chains, branches, and rings; allotropes: diamond, graphite, fullerene
- Hydrocarbons: alkanes (CnH2n+2, single), alkenes (CnH2n, double), alkynes (CnH2n−2, triple)
- Homologous series: same general formula, differ by CH2, similar chemical properties, gradation in physical properties
- IUPAC naming: root (meth/eth/prop/but) + suffix (-ane/-ene/-yne) + functional group suffix (-ol/-al/-one/-oic acid)
- Combustion: hydrocarbons + O2 → CO2 + H2O; saturated = clean flame, unsaturated = sooty
- Oxidation: alcohols → aldehydes/acids (alk. KMnO4); Addition: unsaturated + H2 → saturated (Ni catalyst); Substitution: saturated + Cl2 → chlorinated (sunlight)
- Ethanol: fermentation of sugars; dehydration gives ethene; methanol is lethal
- Ethanoic acid (vinegar): reacts with carbonates, alcohols (esterification: produces fruity-smelling ester)
- Soap vs detergent: soap fails in hard water (scum); detergent works; both clean via micelle formation
Real-World Connections
LPG and CNG are hydrocarbon fuels; synthetic polymers (plastic, nylon) are carbon compounds; vanaspati ghee is made by hydrogenation; soaps and detergents for cleaning; alcohol in sanitisers.
Quick Self-Test (5 Questions)
- What is the most important concept you learned from this chapter?
- Can you write three key equations/formulae from this chapter from memory?
- Draw a labelled diagram relevant to this chapter without looking at your notes.
- Explain one real-world application of a concept from this chapter.
- What is one common mistake students make in this chapter, and how can you avoid it?
Further Study
- NCERT Textbook Chapter 4
- NCERT Exemplar Problems
- Bright Tutorials Detailed Notes: ch04-carbon-compounds.html
- Bright Tutorials Practice Questions: ch04-carbon-compounds.html
- Previous Year CBSE Board Papers