NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations Important Questions (1, 2, 3 and 5 Markers)
Here are the important questions (1,2,3 and 5 Marks) for CBSE Class 10 Science Chapter 1 Chemical Reactions and Equations. The important questions we have compiled will help the students to brush up on their knowledge about the subject. Students can practice Class 10 Science chapter 1 important questions to understand the subject better and improve their performance in the board exam. The solutions provided here will also give students an idea about how to write the answers. Take Free Online MCQ Test for Class 10.
List of Important Question for CBSE Class 10 Science Chapter 1 Chemical Reactions & Equations
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Chemical Reaction and Equations MCQs
Class 10 Science Chemical Reaction and Equations MCQs (1 Marks)
1. Which among the following is (are) double displacement reaction(s)?
(i) Pb +CuCl2 → PbCl2 + Cu
(ii) Na2SO4 + BaCl2 → BaSO4 + 2NaCl
(iii) C + O2 → CO2
(iv) Zn+ 2HCl → ZnCl2 + H2
a) (i) and (iv)
b) (ii) only
c) (i) and (ii)
d) (iii) and (iv)
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2. Which of the following is not a physical change?
a) Boiling of water to give water vapour
b) Melting of ice to give water
c) Dissolution of salt water
d) Combustion of liquefied Petroleum Gas (LPG)
3. Which of the following observations help(s) us to determine that a chemical change has taken place?
a) Change in temperature
b) Evolution of gas
c) Change in colour
d) All of these
4. The following reaction is used for preparation of oxygen gas in the laboratory Heat 2KClO3(s) → 2KCl (s) +3 O2 (g)
Which of the following statement(s) is (are) correct about the reaction?
a) It is a decomposition reaction and endothermic in nature.
b) It is a combination reaction
c) It is a decomposition reaction and is accompanied by release of heat.
d) It is a photo chemical decomposition reaction and exothermic in nature.
5. Chemically the rust is
a) Ferric sulphate
b) Hydrated ferrous oxide
c) Ferric oxide
d) Hydrated ferric oxide
Ans: 1. b) 2.d) 3.d) 4.a) 5. d)
Chemical Reaction and Equations Important Question of 1 Marks Very Short Answer Questions
1. Identify in the following reaction:
2. PbO +C→2Pb +CO
a) The substance oxidised and
b) The substance reduced.
- Carbon is oxidized to CO.
- PbO is getting reduced to Pb.
2. A shiny brown coloured element “x” on heating in air becomes black in colour. Name the element “x” and the black coloured compound formed.
Ans: Element ‘x’ is Copper and the black coloured compound is cupric oxide CuO
Chemical Reaction and Equations Important Question of 2 Marks Short Answer Type Questions
1. Classify the following reaction as combination, decomposition, displacement & double displacement reactions:
a) BaCl2 +H2SO4 → BaSO4 +2HCl
Ans: Double displacement reaction.
b) 3CuSO4+ 2Al→ Al2 (SO4)3 +3Cu
Ans: Displacement reaction.
c) ZnCO3 →ZnO +CO2
Ans: Decomposition reaction.
d) C +O2→CO2
Ans: Combination reaction.
2. What is a precipitation reaction? Give an example.
Ans: Reaction in which an insoluble substance or precipitate is formed Na2SO4 + BaCl2→BaSO4+2NaCl
Chemical Reaction and Equations Important Question of 3 Marks Short Answer Type Questions
1. Give an example, each for thermal decomposition and photochemical decomposition reactions.Write balanced equation for the same.
Ans: Thermal decomposition – Heating of lime stone.
CaCO3→CaO +CO2 Photochemical decomposition – Action of light on silver bromide. 2AgBr→2Ag +Br2
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Chemical Reaction and Equations Important Question of 5 Marks Very Long Answer Type Questions
1. (i) Write chemical equations for the following and balance them.
a) Zinc carbonate(s) →Zinc oxide + Carbon dioxide
Ans: ZnCO3 →ZnO +CO2
b) Potassium bromide (aq) + Barium iodide (aq) → Potassium iodide + Barium bromide.
Ans: 2KBr + BaI2 → 2KI + BaBr2
c) Nitrogen + Hydrogen → Ammonia
Ans: N2 + 3H2 → 2NH3
ii) What happens when electricity is passed through acidified water?
Ans: Decomposition of water takes place resulting in the formation of hydrogen and oxygen
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