Chemical Reactions and Equations Practice
Solve chapter-level practice questions for Chemical Reactions and Equations with reveal-only solutions and quick revision support.
Practice Set 1 - Basics and Balancing
1-mark and 2-mark questions on observations and balancing.
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Practice Set 2 - Reaction Types
Classification-based short answers.
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Practice Set 3 - 3-Mark Board Style
Medium-length explanatory answers.
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Practice Set 4 - Long Answers
5-mark pattern with explanation and equations.
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Practice Set 5 - Mixed Revision
Mixed 1-mark to 5-mark revision questions.
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Quick Q&A Before You Revise
Why do we never change subscripts while balancing equations?
Changing a subscript changes the identity of the substance itself. For example, H2O and H2O2 are different compounds, so only coefficients may be changed during balancing.
How do I quickly identify a displacement reaction?
Look for an element plus a compound on the reactant side and a new element plus a new compound on the product side. Then check whether the free element is more reactive.
Is every double displacement reaction a precipitation reaction?
No. Some double displacement reactions produce a precipitate, while others are neutralisation reactions that form salt and water.
Why is respiration placed in this chapter?
Respiration is included because it is a real-life exothermic chemical reaction that releases energy from glucose. It helps students see chemistry inside living systems.
What is the easiest way to remember oxidation and reduction?
For Class 10 level, remember oxidation as gain of oxygen or loss of hydrogen, and reduction as loss of oxygen or gain of hydrogen. Then test the reaction using these clues.
Why does rusting happen faster near the sea?
Coastal air contains more moisture and dissolved salts, which speed up corrosion. That is why iron structures near the sea rust faster.
Can an exothermic reaction also be a combination reaction?
Yes. The reaction between quicklime and water is both exothermic and combination because it releases heat and forms a single product.
What should I include in a 3-mark chemistry answer from this chapter?
Write the balanced equation, name the reaction type, and add one reason or observation. This combination usually covers the expected marking points.