NCERT Solutions for Class 10 Science Chapter 1

NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations intext questions given on Page 6, Page 10, Page 13 and Exercises in English and Hindi Medium free to download for session 2020-21.

Hindi Medium solutions given on पेज 6 के उत्तर or पेज 11 के उत्तर or पेज 15 के उत्तर and अभ्यास के प्रश्न उत्तर are also free to use online or download in PDF form for the new academic session 2020-21. Download NCERT Solutions as well as NCERT Solutions Offline Apps 2020-2021 based on latest NCERT Books 2020-21 which works without internet.

NCERT Solutions for Class 10 Science Chapter 1

Class:	10
Subject:	Science – विज्ञान
Chapter 1:	Chemical Reactions and Equations

10th Science Chapter 1 Answers in English & Hindi Medium

NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations Exercises and intext questions in English and Hindi Medium updated for new academic session 2020-21 to use online or download in PDF form free. All the solutions are updated for UP Board, CBSE Board, MP Board, etc., who are use NCERT Books 2020-21 as course books and following the latest CBSE Curriculum 2020-21.

10th Science Chapter 1 Answers in English Medium
10th Science Chapter 1 Answers in Hindi Medium
10th Science Chapter 1 Answers in PDF Form

10 Science – Chemical Reactions and Equations – Important Questions

Question 1:
What is meant by a skeletal chemical equation? Using suitable chemical reaction, differentiate between a skeletal chemical equation and a balanced chemical equation.
Answer 1:
If the number of atoms of any element in a chemical equation is not equal on both sides, then it is a skeletal equation. For example:

Here, the number of chlorine and hydrogen atoms are not equal on both sides.
In a Balance equation, the numbers of atoms of different elements on both sides of a chemical equation are equal. For example:

Question 2:
Explain the following terms with examples in each case:
(i) Oxidation and (ii) Reduction.
Answer 2:
(i) Oxidation: it us a process (a) in which oxygen or any electronegative element is added up or (b) hydrogen or any electropositive element is removed. Examples are:
(a)Sulphur burns in the air with a blue flame to form sulphur dioxide. Here oxygen is added up to sulphur.

(b) Hydrogen sulphide combines with iodine to give hydrogen iodine and sulphur.

(ii) Reduction: It is a process in which (a) Hydrogen or an electropositive element is added up.

(b) Oxygen or electronegative element is removed.

Examples are:
(a)Hydrogen reacts with chlorine to form hydrogen chloride.

(b)Copper oxide is reduce with hydrogen.

Question 3:
Why is respiration considered an exothermic reaction? Explain.
Answer 3:
During digestion, food is broken down into simpler substances. Food like rice, potato and bread are made up of carbohydrates. These carbohydrates are further broken down into glucose. Glucose during respiration (inhalation of oxygen) is oxidised with the liberation of energy as shown below. Thus, respiration is an exothermic process.

Important Questions on 10th Science Chapter 1

What is a balanced chemical equation? Why should chemical equations be balanced?

A reaction which has an equal number of atoms of all the elements on both sides of the chemical equation is called a balanced chemical equation.
The law of conservation of mass states that mass can neither be created nor destroyed. Hence, in a chemical reaction, the total mass of reactants should be equal to the total mass of the products. It means that the total number of atoms of each element should be equal on both sides of a chemical equation. Hence, it is for this reason that chemical equations should be balanced.

Why is respiration considered an exothermic reaction? Explain.

Energy in our body is obtained from the food we eat. During digestion, large molecules of food are broken down into simpler substances such as glucose. Glucose combines with oxygen in the cells and provides energy. The special name of this combustion reaction is respiration. Since energy is released in the whole process, it is an exothermic process.

Why are decomposition reactions called the opposite of combination reactions?

Decomposition reactions are those in which a compound breaks down into two or more substances. These reactions require a source of energy to proceed. Thus, they are the exact opposite of combination reactions in which two or more substances combine to give a new substance with the release of energy.

Why do we apply paint on iron articles?

Iron articles are painted because applying paints prevents them from rusting. When painted, the contact of iron articles from moisture and air is cut off. Hence, rusting is prevented their presence is essential for rusting to take place.

Oil and fat containing food items are flushed with nitrogen. Why?

Nitrogen is an inert gas (at room temperature) and does not easily react with oil and fat containing items. On the other hand, oxygen reacts with food substances and makes them rancid. Thus, bags used in packing food items are flushed with nitrogen gas to remove oxygen inside the pack. When oxygen is not present inside the pack, rancidity of oil and fat containing food items is avoided.