In CBSE Class 10 Science Paper, Students will have to answer some questions based on Assertion and Reason. There will be a few questions based on case studies and passage-based as well. In that, a paragraph will be given.
Here we are providing you with Class 10 Science Chapter 1 Chemical Reactions and Equations Case Study Questions, by practicing this Case Study and Passage Based Questions will help you in your Class 10th Board Exam.
Case Study Chapter 1 Chemical Reactions and Equations
Question 1:
A chemical reaction is a representation of chemical change in terms of symbols and formulae of reactants and products. There are various types of chemical reactions like combination, decomposition, displacement, double displacement, oxidation, and reduction reactions. Reactions in which heat is released along with the formation of products are called exothermic chemical reactions. All combustion reactions are exothermic reactions.
(i) The chemical reaction in which a single substance breaks down into two or simpler substances upon heating is known as
(a) thermal decomposition reaction
(b) photodecomposition reaction
(c) electric decomposition reaction
(d) both (a) and (c)
Answer: (a) The chemical reaction in which a single substance breaks down into two or more simpler substances upon heating is known as thermal decomposition reaction.
(ii) The massive force that pushes the rocket forward through space is generated due to the
(a) combination reaction
(b) decomposition reaction
(c) displacement reaction
(d) double displacement reaction
Answer: (b) The massive force that pushes the rocket forward through space is generated due to the decomposition reaction. Hydrogen peroxide decomposes and provides it with a considerable reaction force thrust.
(iii) A white salt on heating decomposes to give brown fumes and the yellow residue is left behind. The yellow residue left is of
(a) lead nitrate
(b) nitrogen oxide
(c) lead oxide
(d) oxygen gas
Answer: (c) Lead nitrate decomposes to give brown fumes of nitrogen dioxide gas and yellow residue of lead oxide is left behind.
(iv) Which of the following reactions represents a combination reaction?
(a) CaO (s) + H2O (l) → Ca(OH)2 (aq)
(b) CaCO3 (s) → CaO (s) + CO2(g)
(c) Zn(s) + CuSO4 (aq) → ZnSO4 (aq) + Cu(s)
(d) 2FeSO4(s) → Fe2O3 (s) +SO2(g) + SO3(g)
Answer: (a) A reaction in which two or more reactants combine to form a single product is known as a combination reaction.
(v) Complete the following statements by choosing correct type of reaction for X and Y.
Statement 1: The heating of lead nitrate is an example of ‘X’ reaction.
Statement 2: The burning of magnesium is an example of ‘Y’ reaction.
(a) X- Combination, Y- Decomposition
(b) X- Decomposition, Y-Combination
(c) X- Combination, Y-Displacement
(d) X- Displacement, Y-Decomposition
Answer: (b) Heating of lead nitrate to form nitrogen dioxide and lead oxide is an example of thermal decomposition reaction and the burning of magnesium ribbon in the air to form magnesium oxide is an example of combination reaction.
Question 2:
In a chemical reaction, reactants are converted into products. The conversion of reactants into products in a chemical reaction is often accompanied by some features which can be observed easily. These easily observed features which take place as a result of chemical reactions are known as characteristics of chemical reactions. Some important characteristics of chemical reactions are:
(I) Evolution of heat
(II) Formation of a precipitate
(III) Change in color
(IV) Change in temperature
(V) Change in state
Anyone of these general characteristics can tell us whether a chemical reaction has taken place or not.
(i) Reaction of magnesium with air is a/an
| (a) exothermic reaction | (b) endothermic reaction |
| (c) reversible reaction | (d) substitution reaction |
Answer: (a) exothermic reaction
(ii) In the following reaction
Ca2+(aq)+2OH−(aq)⟶Ca(OH)2(s)Ca(aq)2++2OH(aq)−⟶Ca(OH)2(s)
precipitate of calcium hydroxide will be of
| (a) green colour | (b) blue colour | (c) brown colour | (d) white colour |
Answer: (d) white colour
(iii) In the given reaction,
S(s)+O2(g)⟶SO2S(s)+O2(g)⟶SO2
the physical state of SO2 is
| (a) liquid | (b) solid | (c) gaseous | (d) all three |
Answer: (c) gaseous
(iv) Which one of the following processes involves chemical reactions?
| (a) Storing of oxygen gas under pressure in a gas cylinder. |
| (b) Keeping petrol in a china dish in the open. |
| (c) Liquefaction of air. |
| (d) Heating copper wire in the presence of air at high temperatures. |
Answer: (d) Heating copper wire in the presence of air at high temperature.
(v) In which of the following reactions, a high amount of heat energy will be evolved?
| (a) Electrolysis of water | (b) Dissolution of NH4Cl in water |
| (c) Burning of L.P.G. | (d) Decomposition of AgBr in the presence of light |
Answer: (c) Burning of L.P.G.
You can also practice Class 10 Science MCQ Questions for Board Exams.