# Selina solutions for Concise Chemistry Class 8 ICSE chapter 6 - Chemical Reactions [Latest edition]

## Chapter 6: Chemical Reactions

Exercise 1Exercise 2
Exercise 1 [Page 73]

### Selina solutions for Concise Chemistry Class 8 ICSE Chapter 6 Chemical Reactions Exercise 1 [Page 73]

Exercise 1 | Q 1.1 | Page 73

Define a chemical reaction.

Exercise 1 | Q 1.2 | Page 73

What happens during a chemical reaction ?

Exercise 1 | Q 1.3 | Page 73

What do you understand by a chemical bond ?

Exercise 1 | Q 2.1 | Page 73

Give one example each of which illustrates the following characteristics of a chemical reaction:

evolution of a gas

Exercise 1 | Q 2.2 | Page 73

Give one example each of which illustrates the following characteristics of a chemical reaction:

change of colour

Exercise 1 | Q 2.3 | Page 73

Give one example each of which illustrates the following characteristics of a chemical reaction change in state

Exercise 1 | Q 3.1 | Page 73

How do the following help in bringing about a chemical change?

pressure.

Exercise 1 | Q 3.2 | Page 73

How do the following help in bringing about a chemical change?

light.

Exercise 1 | Q 3.3 | Page 73

How do the following help in bringing about a chemical change?

catalyst .

Exercise 1 | Q 3.4 | Page 73

How do the following help in bringing about a chemical change?

heat.

Exercise 1 | Q 4.1 | Page 73

Define; catalyst.

Exercise 1 | Q 4.2 | Page 73

What are (i) positive catalysts and (ii) negative catalysts? Support your answer with one example for each of them.

Exercise 1 | Q 4.3 | Page 73

Name three biochemical catalysts found in the human body.

Exercise 1 | Q 5.1 | Page 73

What do you observe when dilute sulphuric acid is added to granulated zinc?

Exercise 1 | Q 5.2 | Page 73

What do you observe when a few pieces of iron are dropped in a blue solution of copper sulphate?

Exercise 1 | Q 5.3 | Page 73

What do you observe when silver nitrate is added to a solution of sodium chloride?

Exercise 1 | Q 5.4 | Page 73

What do you observe when ferrous sulphate solution is added to an aqueous solution of sodium hydroxide.

Exercise 1 | Q 5.6 | Page 73

What do you observe when when dilute sulphuric acid is added to barium chloride solution ?

Exercise 1 | Q 6.1 | Page 73

Complete and balance the following chemical equations:

N2 + O2  →

Exercise 1 | Q 6.2 | Page 73

Complete and balance the following chemical equations:

"H"_2"S" + "CI"_2  →

Exercise 1 | Q 6.3 | Page 73

Complete and balance the following chemical equations

Na + H2 O →

Exercise 1 | Q 6.4 | Page 73

Complete and balance the following chemical equations

NaCI + AgNO_3  →

Exercise 1 | Q 6.5 | Page 73

Complete and balance the following chemical equations:

Zn + "H"_2"SO"_4  →

(dil)

Exercise 1 | Q 6.6 | Page 73

Complete and balance the following chemical equations:

Fe "SO"_4  + NaOH  →

(aq.)          (aq.)

Exercise 1 | Q 6.7 | Page 73

Complete and balance the following chemical equations:

$\ce{Pb(NO3)2->[heat]}$ _________

Exercise 1 | Q 6.8 | Page 73

Complete and balance the following chemical equations:

Ba"CI"_2   +  "H"_2"SO"_4   →

(aq.)           (aq.)

Exercise 2 [Pages 85 - 86]

### Selina solutions for Concise Chemistry Class 8 ICSE Chapter 6 Chemical Reactions Exercise 2 [Pages 85 - 86]

Exercise 2 | Q 1.01 | Page 85

Fill in the blank

A reaction in which two or more substances combine to form a single substance is called a ............ reaction.

Exercise 2 | Q 1.02 | Page 85

Fill in the blanK

A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.

Exercise 2 | Q 1.03 | Page 85

Fill in the blank.
The formation of gas bubbles in a liquid during a reaction is called ......................

Exercise 2 | Q 1.04 | Page 85

Fill in the blank.

The reaction between an acid and a base is called ..................

Exercise 2 | Q 1.05 | Page 85

Fill in the blank .

Soluble bases are called ............

Exercise 2 | Q 1.06 | Page 85

Fill in the blank.

The chemical change involving iron and hydrochloric acid illustrates a ...............reaction.

Exercise 2 | Q 1.07 | Page 85

Fill in the blank

In the type of reaction called ....................................., ions two compounds exchange their positive and negative radicals ions respectively.

Exercise 2 | Q 1.08 | Page 85

Fill in the blank

A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.

Exercise 2 | Q 1.09 | Page 85

Fill in the blank

The chemical reaction between hydrogen and chlorine is a ................ reaction

Exercise 2 | Q 1.1 | Page 85

Fill in the blank

When a piece of copper is added to silver nitrate solution, it turns ............in colour.

Exercise 2 | Q 2.1 | Page 86

Classify the following reactions as combination . Also balance the equations.

Also balance the equations.
(a) $\ce{CaCO3(s)->[heat]CaO(s)+CO2(g)}$
(b) Zn(s) +"H"_2"SO"_4  →  "ZnSO"_4 (S) + "H"_2 (g)

(c) "AgNO"_3 (aq)  + NaCI (aq) → Ag CI (S) + "NaNO"_3

(d) "NH"_3 (g) + HCI (g)  → "NH"_4 CI (S)

(e) "CuSO"_4 (aq)  + "H"_2"S" (g)  → CuS (S) + "H"_2"SO"_4 (I)

(f) Zn (S) + "CuSO"_4 (aq)  → "ZnSO"_4 N  (aq) + Cu  (s)

(g)$\ce{Ca(s)O2(g)->[heat]CaO(s)}$

(H) NaOH + HCI  → NaCI + "H"_2"O"

(I) KOH + "H"_2"SO"_4  → "K"_2"SO"_4  + "H"_2"O"

Exercise 2 | Q 2.2 | Page 86

Classify the following reactions as decomposition, Also balance the equations.

(A) $\ce{CaCO3(s)->[heat]CaO(s)+CO2(g)}$

(B) Zn(s) +"H"_2"SO"_4  →  "ZnSO"_4 (S) + "H"_2 (g)

(C) "AgNO"_3 (aq)  + NaCI (aq) → Ag CI (S) + "NaNO"_3

(D) "NH"_3 (g) + HCI (g)  → "NH"_4 CI (S)
(E) "CuSO"_4 (aq)  + "H"_2"S" (g)  → CuS (S) + "H"_2"SO"_4 (I)

(F) Zn (S) + "CuSO"_4 (aq)  → "ZnSO"_4 N  (aq) + Cu  (s)

(g) $\ce{Ca(s)O2(g)->[heat]CaO(s)}$

(H) NaOH + HCI  → NaCI + "H"_2"O"

(I) KOH + "H"_2"SO"_4  → "K"_2"SO"_4  + "H"_2"O"

Exercise 2 | Q 2.3 | Page 85

Classify the following reactions as decomposition, Also balance the equations.

(A) $\ce{CaCO3(s)->[heat]CaO(s)+CO2(g)}$

(B) Zn(s) +"H"_2"SO"_4  →  "ZnSO"_4 (S) + "H"_2 (g)

(C) "AgNO"_3 (aq)  + NaCI (aq) → Ag CI (S) + "NaNO"_3

(D) "NH"_3 (g) + HCI (g)  → "NH"_4 CI (S)
(E) "CuSO"_4 (aq)  + "H"_2"S" (g)  → CuS (S) + "H"_2"SO"_4 (I)

(F) Zn (S) + "CuSO"_4 (aq)  → "ZnSO"_4 N  (aq) + Cu  (s)

(g) $\ce{Ca(s)O2(g)->[heat]CaO(s)}$

(H) NaOH + HCI  → NaCI + "H"_2"O"

(I) KOH + "H"_2"SO"_4  → "K"_2"SO"_4  + "H"_2"O"

Exercise 2 | Q 2.4 | Page 85

Classify the following reactions as decomposition, Also balance the equations.

(A) $\ce{CaCO3(s)->[heat]CaO(s)+CO2(g)}$

(B) Zn(s) +"H"_2"SO"_4  →  "ZnSO"_4 (S) + "H"_2 (g)

(C) "AgNO"_3 (aq)  + NaCI (aq) → Ag CI (S) + "NaNO"_3

(D) "NH"_3 (g) + HCI (g)  → "NH"_4 CI (S)
(E) "CuSO"_4 (aq)  + "H"_2"S" (g)  → CuS (S) + "H"_2"SO"_4 (I)

(F) Zn (S) + "CuSO"_4 (aq)  → "ZnSO"_4 N  (aq) + Cu  (s)

(g) $\ce{Ca(s)O2(g)->[heat]CaO(s)}$

(H) NaOH + HCI  → NaCI + "H"_2"O"

(I) KOH + "H"_2"SO"_4  → "K"_2"SO"_4  + "H"_2"O"

Exercise 2 | Q 2.5 | Page 85

Classify the following reactions as  neutralization .Also balance the equations.

Also balance the equations.

(A) $\ce{CaCO3(s)->[heat]CaO(s)+CO2(g)}$

(B) Zn(s) +"H"_2"SO"_4  →  "ZnSO"_4 (S) + "H"_2 (g)

(C) "AgNO"_3 (aq)  + NaCI (aq) → Ag CI (S) + "NaNO"_3

(D) "NH"_3 (g) + HCI (g)  → "NH"_4 CI (S)
(E) "CuSO"_4 (aq)  + "H"_2"S" (g)  → CuS (S) + "H"_2"SO"_4 (I)

(F) Zn (S) + "CuSO"_4 (aq)  → "ZnSO"_4 N  (aq) + Cu  (s)

(G) $\ce{Ca(s)O2(g)->[heat]CaO(s)}$

(H) NaOH + HCI  → NaCI + "H"_2"O"

(I) KOH + "H"_2"SO"_4  → "K"_2"SO"_4  + "H"_2"O"

Exercise 2 | Q 3.1 | Page 86

Define precipitation.

Exercise 2 | Q 3.2 | Page 86

Define neutralization.

Exercise 2 | Q 3.3 | Page 86

Define catalyst.

Exercise 2 | Q 4.1 | Page 86

Explain the following types of chemical reactions giving two examples for them combination reaction.

Exercise 2 | Q 4.2 | Page 86

Explain the following types of chemical reactions giving two examples for each of them decomposition reaction .

Exercise 2 | Q 4.3 | Page 86

Explain the following types of chemical reactions giving two examples for each of them displacement reaction.

Exercise 2 | Q 4.4 | Page 86

Explain the following types of chemical reactions giving two examples for each of them double decomposition reaction.

Exercise 2 | Q 5.1 | Page 86

Write the missing reactants and products and balance the equations.

NaOH + ............... → NaCI + ...................

Exercise 2 | Q 5.2 | Page 86

Write the missing reactants and products and balance the equations.

$\ce{KCIO3 ->[heat]}$ ___________+ ____________

Exercise 2 | Q 5.3 | Page 86

Write the missing reactants and products and balance the equations.

................+ HCI → NaCI + "H"_2"O" + .........................

Exercise 2 | Q 6.1 | Page 86

How will you obtain Magnesium oxide from magnesium.

Also give balanced equations for the reactions

Exercise 2 | Q 6.2 | Page 86

How will you obtain  Silver chloride from silver nitrate.

Also give balanced equations for the reactions

Exercise 2 | Q 6.3 | Page 86

How will you obtain  Nitrogen dioxide from lead nitrate.
Also give balanced equations for the reactions

Exercise 2 | Q 6.4 | Page 86

How will you obtain Zinc chloride from zinc.

Also give balanced equations for the reactions

Exercise 2 | Q 6.5 | Page 86

How will you obtain Ammonia from nitrogen.
Also give balanced equations for the reactions

Exercise 2 | Q 7.1 | Page 86

What do you observe when Iron nail is kept in copper sulphate solution for sometime.

Exercise 2 | Q 7.2 | Page 86

What do you observe when Phenolphthalein is added to sodium hydroxide solution.

Exercise 2 | Q 7.3 | Page 86

What do you observe when Blue litmus paper is dipped in dilute hydrochloric acid.

Exercise 2 | Q 7.4 | Page 86

What do you observe when Lead nitrate is heated.

Exercise 2 | Q 7.5 | Page 86

What do you observe when Magnesium ribbon is burnt in oxygen.

Exercise 2 | Q 7.6 | Page 86

What do you observe when Ammonia is brought in contact of hydrogen chloride.gas.

Exercise 2 | Q 8.1 | Page 86

Give reason .

A person suffering from acidity is advised to take an antacid.

Exercise 2 | Q 8.2 | Page 86

Give reason.

Acidic soil is treated with quick lime.

Exercise 2 | Q 8.3 | Page 86

Give reason.

Wasp sting is treated with vinegar.

Exercise 2 | Q 9 | Page 86

What is meant by the metal reactivity series ? State its importance, (any two points).

Exercise 2 | Q 10.1 | Page 86

What are oxides ?

Exercise 2 | Q 10.2 | Page 86

Give two examples Basic oxide .

Exercise 2 | Q 10.3 | Page 86

Give two examples of  oxides.

Acidic oxide.

Exercise 2 | Q 10.4 | Page 86

Give two examples of  oxides.

Amphoteric oxide

Exercise 2 | Q 10.5 | Page 86

Give two examples of oxides.

Neutral oxide

Exercise 2 | Q 11.1 | Page 86

Define exothermic reactions. Give two examples of each.

Exercise 2 | Q 11.2 | Page 86

Define  endothermic reactions. Give two examples of each.

Exercise 2 | Q 12.1 | Page 86

State the effect of an endothermic reaction.

Exercise 2 | Q 12.2 | Page 86

State the effect of  an exothermic reaction on the surroundings.

Exercise 2 | Q 13.1 | Page 86

What do you observe when an acid is added to a basic solution.

Exercise 2 | Q 13.2 | Page 86

What do you observe when ammonium chloride is dissolved in water.

## Chapter 6: Chemical Reactions

Exercise 1Exercise 2

## Selina solutions for Concise Chemistry Class 8 ICSE chapter 6 - Chemical Reactions

Selina solutions for Concise Chemistry Class 8 ICSE chapter 6 (Chemical Reactions) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CISCE Concise Chemistry Class 8 ICSE solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com provide such solutions so that students can prepare for written exams. Selina textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Concise Chemistry Class 8 ICSE chapter 6 Chemical Reactions are Classification of Change: Chemical Changes, Chemical Reaction, Indicators of a Chemical Change (Chemical Reaction), Conditions Necessary for Chemical Reactions, Double Displacement Reaction, Oxides, Types of Double Displacement: Precipitation Reaction, Types of Double Displacement: Neutralization Reaction, Neutralization Reactions in Our Daily Life, Reactivity Series of Metals, Types of Chemical Change or Chemical Reaction, Direct Combination (or Synthesis) Reaction, Energy Change in Chemical Reactions, Decomposition Reactions, Single Displacement Reactions.

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