In this post, we provide Class 10 Science Chapter 1 Chemical Reactions and Equations Intext Solutions with simple and easy explanations. These NCERT intext question answers help students understand important concepts like chemical reactions, balanced equations, oxidation, reduction, corrosion, and rancidity. All solutions are prepared according to the latest CBSE syllabus to help students in revision, homework, and exam preparation.
INTEXT SOLUTION
Page No. :- 06
Ques 1 :- Why should a magnesium ribbon be cleaned before burning in air?
Ans: Magnesium is a very reactive metal. When exposed to air, it reacts with oxygen and forms a thin layer of magnesium oxide (MgO) on its surface. This Magnesium oxide layer prevents magnesium from burning properly. Therefore, magnesium ribbon is cleaned before burning to remove the magnesium oxide layer so that it burns easily in air.
OR
Ans: Magnesium ribbon is cleaned before burning because it reacts with oxygen in air to form a layer of magnesium oxide (MgO). This layer prevents proper burning, so it is removed before burning.
Ques 2:- Write the balanced equation for the following chemical reactions.
(i) Hydrogen + Chlorine → Hydrogen chloride
Ans:-
H₂(g) + Cl₂(g) → 2HCl(g)
(ii) Barium chloride + Aluminium sulphate → Barium sulphate +Aluminium chloride
Ans:-
3BaCl₂(aq) + Al₂(SO₄)₃(aq) → 3BaSO₄(s) + 2AlCl₃(aq)
(iii) Sodium + Water → Sodium hydroxide + Hydrogen
Ans:-
2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)
Ques 3:- Write a balanced chemical equation with state symbols for the following reactions.
(i) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.
Ans:-
BaCl₂(aq) + Na₂SO₄(aq) → BaSO₄(s) + 2NaCl(aq)
(ii) Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.
Ans:-
NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)
Page No. :- 10
Ques 1:- A solution of a substance ‘X’ is used for whitewashing.
(i) Name the substance ‘X’ and write its formula.
Ans:- (i) The substance 'X' is Calcium oxide (also called quick lime). Its formula is CaO.
(ii) Write the reaction of the substance ‘X’ named in (i) above with Water.
The balanced chemical reaction is:
(ii) CaO (s) + H2O (l) → Ca(OH)2 (s) + heat
Explanation:
When calcium oxide (quick lime) reacts with water, it forms calcium hydroxide (slaked lime), which is used for whitewashing. This reaction releases heat, so it is an exothermic reaction.
Ques 2:- Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.
Ans:- The gas is hydrogen.
During electrolysis, water decomposes to form hydrogen and oxygen gases.
electrolysis
2H2O (l) --------> 2H2 (g) + O2 (g)
In the above reaction, the balanced chemical equation shows that on electrolysis, water decomposes to form hydrogen and oxygen in the ratio of 2 : 1 by volume. Thus the amount of hydrogen gas produced is double the amount of oxygen produced.
Page No. :- 13
Ques 1:- Why does the colour of copper sulphate solution change when an iron nail is dipped in it ?
Ans:- The blue colour of copper sulphate solution changes because iron is more reactive than copper. Therefore, iron displaces copper from copper sulphate solution and iron sulphate is formed, which is light green in colour.
CuSO4 (aq) + Fe (s) → FeSO4 (aq) + Cu (s)
(Blue) (Light green)
Ques 2 :- Give an example of a double displacement reaction other than the one given in Activity 1.10.
Ans:-
AgNO3 (aq) + NaCl (aq) --------> AgCl (s) + NaNO3 (aq)
|
AgNO3 Silver nitrate |
NaCl Sodium chloride |
AgCl Silver chloride |
NaNO3 Sodium nitrate |
Ques 3 :- Identify the substances that are oxidised and the substances that are reduced in the following reactions.
(i) 4Na (s) + O2 (g) -------→ 2Na2O (s)
Ans. (i) In this reaction, sodium (Na) is oxidised to sodium oxide (Na2O).
This means that oxygen (O2) has been reduced.
(ii) CuO (s) + H2 (g) → Cu (s) + H2O (l)
Ans. (ii) In this reaction, hydrogen (H2) is oxidised to water (H2O), while copper(II) oxide (CuO) is reduced to copper (Cu).
We hope these Class 10 Science Chapter 1 Chemical Reactions and Equations Intext Solutions helped you understand the chapter easily. These NCERT solutions are useful for revision, homework, and board exam preparation. Keep practicing chemical equations and important reactions regularly to score better in exams.
FAQs
1. What are Chemical Reactions and Equations?
Chemical reactions are processes in which new substances are formed from reactants. Chemical equations are symbolic representations of these reactions using chemical formulas.
2. Why are chemical equations balanced?
Chemical equations are balanced to satisfy the law of conservation of mass. The number of atoms of each element must be equal on both sides of the equation.
3. What is a combination reaction?
A combination reaction is a reaction in which two or more substances combine to form a single product.
4. What is oxidation and reduction?
Oxidation is the addition of oxygen or removal of hydrogen, while reduction is the removal of oxygen or addition of hydrogen.
5. Why are NCERT intext solutions important for Class 10 Science?
NCERT intext solutions help students understand important concepts clearly and prepare effectively for CBSE board exams.
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