Every Book Back multiple-choice question from Types of Chemical Reactions (10th Standard Science, Samacheer Kalvi) — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
\(\text{H}_{2(g)} + \text{Cl}_{2(g)} \rightarrow 2\text{HCl}_{(g)}\) is a
- A. Decomposition Reaction
- B. Combination ReactionCorrect
- C. Single Displacement Reaction
- D. Double Displacement Reaction
Explanation. Two elements, hydrogen and chlorine, combine to form a single compound as product. Therefore, this represents a combination reaction.
Q2
Photolysis is a decomposition reaction caused by ___________
- A. heat
- B. electricity
- C. lightCorrect
- D. mechanical energy
Explanation. Photolysis is a chemical decomposition reaction where a compound is split into simpler substances by the absorption of light energy.
Q3
A reaction between carbon and oxygen is represented by \(\text{C}_{(s)} + \text{O}_{2(g)} \rightarrow \text{CO}_{2(g)} + \text{Heat}\). In which of the type(s), the above reaction can be classified?
(i) Combination Reaction
(ii) Combustion Reaction
(iii) Decomposition Reaction
(iv) Irreversible Reaction
- A. i and ii
- B. i and iv
- C. i, ii and iii
- D. i, ii and ivCorrect
Explanation. Carbon and oxygen combine to form carbon dioxide, representing a combination. It reacts with oxygen releasing heat, representing combustion. Since the gas escapes, the reaction is irreversible.
Q4
The chemical equation \(\text{Na}_2\text{SO}_{4(aq)} + \text{BaCl}_{2(aq)} \rightarrow \text{BaSO}_{4(s)}\downarrow + 2\text{NaCl}_{(aq)}\) represents which of the following types of reaction?
- A. Neutralisation
- B. Combustion
- C. PrecipitationCorrect
- D. Single displacement
Explanation. The reaction between sodium sulphate and barium chloride aqueous solutions forms an insoluble white precipitate of barium sulphate, which is a precipitation reaction.
Q5
Which of the following statements are correct about a chemical equilibrium?
(i) It is dynamic in nature
(ii) The rate of the forward and backward reactions are equal at equilibrium
(iii) Irreversible reactions do not attain chemical equilibrium
(iv) The concentration of reactants and products may be different
- A. i, ii and iiiCorrect
- B. i, ii and iv
- C. ii, iii and iv
- D. i, iii and iv
Explanation. Chemical equilibrium is dynamic, forward and backward reaction rates are equal, and it is only attained in reversible reactions, not irreversible ones.
Q6
A single displacement reaction is represented by \(\text{X}_{(s)} + 2\text{HCl}_{(aq)} \rightarrow \text{XCl}_{2(aq)} + \text{H}_{2(g)}\). Which of the following(s) could be \(\text{X}\)?
(i) Zn
(ii) Ag
(iii) Cu
(iv) Mg
Choose the best pair.
- A. i and ii
- B. ii and iii
- C. iii and iv
- D. i and ivCorrect
Explanation. Zinc and magnesium are more reactive than hydrogen and lie above it in the reactivity series, allowing them to displace hydrogen from hydrochloric acid.
Q7
Which of the following is not an "element + element \(\rightarrow\) compound" type reaction?
- A. \(\text{C}_{(s)} + \text{O}_{2(g)} \rightarrow \text{CO}_{2(g)}\)
- B. \(2\text{K}_{(s)} + \text{Br}_{2(l)} \rightarrow 2\text{KBr}_{(s)}\)
- C. \(2\text{CO}_{(g)} + \text{O}_{2(g)} \rightarrow 2\text{CO}_{2(g)}\)Correct
- D. \(4\text{Fe}_{(s)} + 3\text{O}_{2(g)} \rightarrow 2\text{Fe}_2\text{O}_{3(s)}\)
Explanation. In the reaction between carbon monoxide and oxygen, carbon monoxide is a compound, not an element. Therefore, it is a compound-element combination reaction.
Q8
Which of the following represents a precipitation reaction?
- A. \(\text{A}_{(s)} + \text{B}_{(s)} \rightarrow \text{C}_{(s)} + \text{D}_{(s)}\)
- B. \(\text{A}_{(s)} + \text{B}_{(aq)} \rightarrow \text{C}_{(aq)} + \text{D}_{(l)}\)
- C. \(\text{A}_{(aq)} + \text{B}_{(aq)} \rightarrow \text{C}_{(s)} + \text{D}_{(aq)}\)Correct
- D. \(\text{A}_{(aq)} + \text{B}_{(s)} \rightarrow \text{C}_{(aq)} + \text{D}_{(l)}\)
Explanation. A precipitation reaction involves two aqueous reactants reacting to form an insoluble solid product, which precipitates out of the solution.
Q9
The pH of a solution is 3. Its \([\text{OH}^-]\) concentration is
- A. \(1 \times 10^{-3}\text{ M}\)
- B. \(3\text{ M}\)
- C. \(1 \times 10^{-11}\text{ M}\)Correct
- D. \(11\text{ M}\)
Explanation. Since \(\text{pH} = 3\), the \(\text{pOH}\) is \(14 - 3 = 11\). The hydroxide ion concentration is therefore \(10^{-11}\text{ M}\).
Q10
Powdered \(\text{CaCO}_3\) reacts more rapidly than flaky \(\text{CaCO}_3\) because of ___________.
- A. large surface areaCorrect
- B. high pressure
- C. high concentration
- D. high temperature
Explanation. Powdering a solid reactant increases its surface area, exposing more particles to collisions and thus increasing the reaction rate.
About these Types of Chemical Reactions questions
These are the Book Back multiple-choice questions for Types of Chemical Reactions from the Tamil Nadu State Board (Samacheer Kalvi) 10th Standard Science syllabus. Each question shows the correct option and an original, step-by-step explanation so you understand the method, not just the answer. Use the answer key above to jump to any question, then take the practice test to check yourself under exam-like conditions.
Frequently asked questions
How many MCQs are there in Types of Chemical Reactions?
This chapter has 10 book-back multiple-choice questions, each with the correct answer and a step-by-step explanation.
Are these 10th Standard Science MCQs free to practise online?
Yes. Every question, answer and explanation here is free, and you can also take them as a timed practice test.
Where can I find the Types of Chemical Reactions book-back answers?
The correct option for each question is highlighted on this page with a worked explanation, plus a quick answer-key summary at the top.
