Chapter 1 of Science Subject of Class 10 is “Chemical Reactions and Equations”. Practice Questions [ Extra Questions ] for Class 10 Science Chapter 1 are provided on this page.

Class 10 Science Chapter 1 : Chemical Reactions and Equations

Chemical Reaction and Equation is the first chapter of class 10 science ncert book. Apart from the ncert solutions of class 10 science chapter 1 , here we have provided the extra question for practice of chapter 1 Chemical Reaction and equation.

These questions covers the majority of topics of the class 10 science chapter 1 like – oxidation, reductions, types of chemical equations, balanced chemical equations, Types of Chemical Reactions , etc

Chapter 1 : Chemical Reactions and Equations ( Practice Questions )

Subject	Science
Class	Class X
Chapter	Chapter 1 : Chemical Reactions and Equations
Study Material	Practice Questions ( Extra Question for Practice )
Total Questions	35 Questions
Text Book	NCERT Text Book

Class 10 Science Chapter 1 : Chemical Reactions and Equations Practice Questions (Extra Question Answer )

Ques. 1 : What is Rancidity ?
Answer : Rancidity can be defined as a phenomenon due to which a substance changes the taste or flavour of food item because of oxidation.

Ques. 2 : What is the cause of Rancidity ?
Answer : Rancidity is caused because of oxidation of oil and fats

Ques. 3 : How can we prevent Rancidity ?
Answer : We can prevent rancidity by following ways –

• By oxidising anti-oxidants.
• BY keeping a food item in an inert atmosphere.

Ques. 4 : What are anti-oxidants ?
Answer : Anti – oxidants are the chemicals used to prevent oxidation.

Ques. 5 : What is corrosion ?
Answer : Corrosion is a process in which the surface of metals gets eaten up by some gases present in the atmosphere when metals reacts with these gases.
OR When a metals is attacked by substance around it such as moisture , acids, etc. it is said to corrode and this process is known as Corrosion.

Ques. 6 : What is Galvanisation ?
Answer : Galvanisation is defined as a process of coating of Zinc metal over the Fe⁺² article.

Ques. 7 : What is the water of crystallisation ?
Answer : The water molecule which form apart of the structure of a crystal are called water of crystallisation.

Ques. 8 : Give some example of chemical having water of crystallisation
Answer : Example 1 : FeSO4.7H2O [ Iron Sulphate Heptohydrate ]
Example 2 : CuSO4. 5H2O [ Copper Sulphate Pentahydrate ]
Example 3 : CaSO4. 2H2O [ Calcium Sulphate dihydrate ]

Ques. 9 : What is Oxidation ?
Answer : Those reaction in which addition of oxygen to a substance or removal of hydrogen from a substance take place .
Example : 2Cu + O₂ + Heat -> 2 CuO

Ques. 10 : What is Reduction ?
Answer : Those reaction in which addition of hydrogen to a substance and removal of oxygen takes place are called Reduction.
Example : CuO + H₂ + Heat -> Cu + H₂O

Ques. 11 : What is Oxidising Agent ?
Answer : Substance which gives oxygen for oxidation or removes hydrogen are known as oxidising agents.

Ques. 12 : What is Reducing Agents ?
Answer : Substance which provides hydrogen for reduction or removes oxygen are known as Reducing Agents.

Ques. 13 : What is Physical Change
Answer : It is a change in which no new substance is formed and can be reversed again. For example : Filling a balloon , etc.

Ques. 14 : What is Chemical Change ?
Answer : It is a change in which a new substance is formed and cannot be reversed again. For Example : Cooking of Food ,etc.

Ques. 15 : What are Reactants and Products ?
Answer : Reactant are the substance which reacts with each other to form a new substance.
Products are the substance which forms when reactants react with each other.
Cu + O₂ -> CuO
CU and O₂ are Reactants
CuO is a Product

Ques. 16 : What is a chemical Equation and Word Equation?
Answer : The symbolic representation of a true chemical change is called a chemical equation.
OR It is a method of representing a chemical reaction with the help of symbols and formulas of the substance involved in it whereas Word Equation contains names of products and reactants.

Ques. 17 : What are Chemical Reactions ?
Answer : These are the processes in which new substance with new properties are formed.

Ques. 18 : “Skeletal Chemical Equation” Define it ?
Answer : Those chemical equation having different masses on both side of equation are called skeletal chemical equation

Ques. 19 : What is a balanced Equation ?
Answer : Those chemical equation which have equal masses or equal number of atoms on both sides of equation are known as Balanced Chemical Equation.

Ques. 20 : To which side the arrow points in a chemical equation ?
Answer : The arrow head points towards the products, and shows the direction of the reaction.

Ques. 21 : Why do we need to balance the chemical equation ?
Answer : The number of atoms of each element remains same before and after chemical reaction. Therefor we need to balance a chemical equation so that it obeys the law of conservation by mass.

Ques. 22 : What are the methods to balance a chemical equation ?
Answer : There are two methods to balance a chemical equations –

• Hit and Trial Method
• Partial Equation Method

Ques. 23 : What are the limitations of a balanced chemical equation ?
Answer : The limitations of Balanced Chemical Equation are –

• It does not represent the Physical state of Reactants and Products.
• It does not represent the speed of the reactions.
• It does not represent whether the reaction is reversible or irreversible.
• It does not tell about the extent of reactions.
• It does not tell about the medium in which reaction takes place.

Ques. 24 : How can we make a chemical equation more informative ?
Answer : We can make a chemical equation more informative by following ways –

• We can represent the Physical state of reactants and Products.
• We can use symbols (up arrow and down arrow) to show whether the element is gas or a precipitate.
• We cab write the reaction conditions above the arrow.
• We can write the medium in which reaction takes place.

Ques. 25 : What are Exothermic Reactions ?
Answer : Those reactions in which heat is along with the formation of products .
Example of Exothermic Reactions : Burning of Natural Gas .
CH4 + 2O2 ->CO2 + 2H2O

Another Example of Exothermic Reactions : During Digestion , food is broken down into simpler substance . As rice , potatoes , Banana and other such food items get converted into carbohydrates. These carbohydrates are broken down to form glucose. The glucose combines with O₂ in cells of our body and provides energy . During this whole process heat is evolved during respiration.
C₆H₁₂O₆ + 6O₂ -> 6CO₂ + 6H₂O + Energy

Another Example of Exothermic Reactions : The decomposition of vegetable matter into compost.

Ques. 26 : What are endothermic Reactions ?
Answer : Those reactions which proceeds with the absorption of Heat along with formation of products.

Ques. 27 : Define Precipitation Reaction
Answer : Any reaction that produces a precipitate ( insoluble substance) are known as Precipitation Reaction.
Example : Na₂SO₄ + BaCl₂ -> BaSO₄ +2NaCl

Ques. 28 : Write the Types of Chemical Reactions.
Answer : Types of Chemical Reactions –

• Combination Reaction
• Decomposition Reaction
• Displacement Reaction
• Double Displacement Reaction
• Oxidation and Reduction

Ques. 29 : What are Combination Reactions ?
Answer : Those reactions in which two roe more substances combine to form a single substance are known as combination Reactions .
Example : CaO + H₂O -> Ca(OH)₂

Ques. 30 : What are Decomposition Reactions ?
Answer : These are those reactions in which a compound splits up into two or more simpler substances.
Example : 2FeSO₄ -> Fe₂SO₃ + SO₂ + SO₃

Ques. 31 : What are Displacement Reactions ?
Answer : Those reactions in which one element takes the place of another element in a compound are known as Displacement Reactions.
Example : Fe + CuSO₄ -> FeSO₄ + Cu

Ques. 32 : What are Double Displacement Reactions ?
Answer : Those reactions in which two compounds react by exchange of ions to form two new compounds are known as Double Displacement Reactions .

Ques. 33 : What are Thermal Decomposition Reactions ?
Answer : Those reactions in which decompositions is brought about by heat are known as Thermal Decomposition Reactions.

Ques. 34 : What is Photo Decomposition Reaction ?
Answer : Those reactions in which Decomposition is carried out by the light are known as Photo Decomposition Reaction.
Example : 2AgBr + Sunlight -> 2Ag + Br

Ques. 35 : What is Electric Decomposition Reactions ?
Answer : Those reaction in which decomposition is brought up by electricity are known as Electric Decomposition Reactions .
Examples : Electrolysis of Water .

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