Class 10 Science Chapter 1: Chemical Reactions and Equations Worksheet (2025 Syllabus)

Multiple Choice Questions

1. What type of reaction is \(2H_2 + O_2 \rightarrow 2H_2O\)?
(a) Combination reaction
(b) Decomposition reaction
(c) Displacement reaction
(d) Double displacement reaction

2. In the reaction \(2HgO \rightarrow 2Hg + O_2\), what type of reaction is this?
(a) Combination reaction
(b) Decomposition reaction
(c) Displacement reaction
(d) Double displacement reaction

3. In the reaction \(Zn + CuSO_4 \rightarrow ZnSO_4 + Cu\), what is being displaced?
(a) Zinc
(b) Copper
(c) Sulphate
(d) Water

4.What type of reaction is characterized by heat being released?
(a) Exothermic
(b) Endothermic
(c) Oxidation
(d) Reduction

5. In a double displacement reaction, what happens?
(a) A more reactive element displaces a less reactive element from its compound
(b) Two elements swap places in two different compounds
(c) A compound breaks down into its elements
(d) Two elements combine to form a compound

6.In the redox reaction
MnO₂ + 4HCl -> MnCl₂ + 2H₂O + Cl₂
(a) MnO₂ is reduced to MnCl₂ & HCl is oxidized to H₂O
(b) MnO₂ is reduced to MnCl₂ & HCl is oxidized to Cl₂
(c) MnO₂ is oxidized to MnCl₂ & HCl is reduced to Cl₂
(d) MnO₂ is oxidized to MnCl₂ & HCl is reduced to H₂O

Answer

1. (a) ,
2. (b),
3. (b),
4. (a),
5. (b)
6. (b) $MnO_2$ is reduced to $MnCl_2$ & $HCl$ is oxidized to $Cl$

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Fill in the blanks:-

1. Addition of hydrogen in a substance in a reaction is known as __________ reaction.
2. In a __________ reaction, two or more substances combine to form a new single substance.
3. Unbalanced reactions are also known as __________.
4. Reactions in which heat is given out along with the products are called __________ reactions.
5. Reactions in which energy is absorbed are known as __________ reactions.
6. When an element displaces another element from its compound, a __________ reaction occurs.
7. Those reactions in which two compounds react by an exchange of ions to form two new compounds are called __________ reactions.
8. Precipitation reactions produce __________ salts.
9. Reduction is the __________ of oxygen or gain of hydrogen.
10. The digestion of food in the body is an example of a __________ reaction.
11. The addition of oxygen to a substance is called __________.
12. When calcium carbonate is heated, it decomposes to give __________ and __________.

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Answers to Fill in the blank Questions