Question 4(2014)
Gas Q turns moist lead acetate paper silvery black. Identify Q. pH of R is 10. What kind of substance is R?
The gas Q is H2S (Hydrogen sulphide).
Pb(CH3COO)2 [colourless] + H2S ⟶ PbS [black] + 2CH3COOH
R is an alkaline substance.
Key Concepts Covered
This question tests your understanding of the following concepts from the chapter Practical Chemistry: Question, Gas, Turns, Moist, Lead, Acetate. These are fundamental topics in Chemistry that students are expected to master as part of the ICSE Class 10 curriculum.
A thorough understanding of these concepts will help you answer similar questions confidently in your ICSE examinations. These topics are frequently tested in both objective and subjective sections of Chemistry 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
- Balance chemical equations before solving numerical problems.
- Learn the periodic table trends and exceptions.
- Understand reaction mechanisms, not just outcomes.
- Use correct IUPAC nomenclature in your answers.
Practice more questions from Practical Chemistry — Chemistry, Class 10 ICSE