# Viraf J. Dalal solutions for Class 9 Simplified ICSE Chemistry chapter 2 - Chemical Changes & Reactions [Latest edition]

## Chapter 2: Chemical Changes & Reactions

Exercise

### Viraf J. Dalal solutions for Class 9 Simplified ICSE Chemistry Chapter 2 Chemical Changes & Reactions Exercise

Exercise | Q 1

Give an example of an endothermic reaction.

Exercise | Q 1

Give one reason why magnetizing a piece of steel is a physical change.

Exercise | Q 1

Explain the Silver nitrate solution is kept in coloured reagent bottles in the laboratory.

Exercise | Q 1.1

State the following reaction represent oxidation or reduction.

$\ce{Fe++->Fe+++}$

• oxidation

• reduction

Exercise | Q 1.1

The reaction can be classified as:

State which of the following type, take place in the reaction is given below.

$\ce{Cl2 + 2Kl->2KCl + l2}$

• Direct combination

• Decomposition reaction

• Simple displacement

• Double decomposition

• Redox reaction

Exercise | Q 1.1

State the following reaction represent oxidation or reduction.

$\ce{Fe++->Fe+++}$

• oxidation

• reduction

Exercise | Q 1.2

State the following reaction represent oxidation or reduction.

$\ce{Cl- ->Cl}$

• oxidation

• reduction

Exercise | Q 1.2

The reaction can be classified as:

State which of the following type, take place in the reaction is given below.

$\ce{2Mg + O2->2MgO}$

• Direct combination

• Decomposition reaction

• Simple displacement

• Double decomposition

• Redox reaction

Exercise | Q 1.2

State whether the following reaction is oxidation or reduction.

$\ce{Na->Na+}$

• Oxidation

• Reduction

Exercise | Q 1.3

State the following reaction represent oxidation or reduction.

$\ce{Cu++->Cu}$

• oxidation

• reduction

Exercise | Q 1.3

The reaction can be classified as:

State which of the following type, take place in the reaction is given below.

$\ce{SO2 + 2H2O + Cl2->2HCl + H2SO4}$

• Direct combination

• Decomposition reaction

• Simple displacement

• Double decomposition

• Redox reaction

Exercise | Q 1.4

State the following reaction represent oxidation or reduction.

$\ce{Ag->Ag+}$

• oxidation

• reduction

Exercise | Q 1.4

The reaction can be classified as:

State which of the following type, take place in the reaction is given below.

$\ce{AgNO3 + HCl->AgCl + HNO3}$

• Direct combination

• Decomposition reaction

• Simple displacement

• Double decomposition

• Redox reaction

Exercise | Q 1.5

State the following reaction represent oxidation or reduction.

$\ce{H->H+}$

• oxidation

• reduction

Exercise | Q 1.5

The reaction can be classified as:

State which of the following type, take place in the reaction is given below.

$\ce{4HNO3->4NO2 + 2H2O + O2}$

• Direct combination

• Decomposition reaction

• Simple displacement

• Double decomposition

• Redox reaction

Exercise | Q 1.6

State the following reaction represent oxidation or reduction.

$\ce{Al->Al+++}$

• oxidation

• reduction

### Viraf J. Dalal solutions for Class 9 Simplified ICSE Chemistry Chapter 2 Chemical Changes & Reactions Additional Questions

Explain the term chemical reaction with special reference to reactants and products.

Give a suitable example with an equation to show the representation of a chemical reaction.

A chemical reaction is often accompanied by external indications or characteristics.

Give two examples where a chemical reaction is accompanied by a change in colour of the reactants and products on completion of the reaction.

Give a balanced equation for a reaction involving the evolution of gas on the addition of dilute acid to sodium sulphite.

Give a balanced equation for a reaction involving the evolution of gas on the addition of dilute acid to calcium carbonate.

Give a balanced equation for the conversion of an ammonium salt to a basic gas.

Give a balanced equation for the conversion of a soluble lead salt to an insoluble lead salt – formed as a white precipitate.

Chemical reactions may proceed with evolution of heat. Give an example.

Chemical reactions may proceed with absorption of heat. Give an example.

Define the following type of chemical change or reaction with a suitable example.

Direct combination reaction or synthesis

Define the following type of chemical change or reaction with a suitable example.

Decomposition reaction

Define the following type of chemical change or reaction with a suitable example.

Displacement reaction or substitution reaction

Define the following type of chemical change or reaction with a suitable example.

Double decomposition reaction

Give a balanced equation for a direct combination reaction involving:

Two elements – one of which is a neutral gas and the other a yellow non-metal

Give a balanced equation for a direct combination reaction involving:

Two elements – one of which is a neutral gas and the other a monovalent metal

Give a balanced equation for a direct combination reaction involving:

Two compounds – resulting in the formation of a weak acid

Give a balanced equation for the following reaction of synthesis involving the formation of:

An acid – from sulphur dioxide gas

Give a balanced equation for the following reaction of synthesis involving the formation of:

An alkali – from a basic oxide – sodium oxide

Give a balanced equation for the following reaction of synthesis involving the formation of:

A salt – from a trivalent metal and a coloured gas.

Convert nitrogen to ammonia by a direct combination reaction.

Convert hydrogen to hydrogen chloride by a direct combination reaction.

Give a balanced equation for thermal decomposition of lead carbonate

Give a balanced equation for thermal decomposition of lead nitrate

Give a balanced equation for thermal decomposition of ammonium dichromate

Give a balanced equation for thermal decomposition of mercury [II] oxide

Give a balanced equation for thermal decomposition of calcium hydroxide

Define a thermal dissociation reaction with a suitable example.

Give an example of a photochemical decomposition reaction.

Name a metallic oxide which on thermal decomposition is reduced to metal.

Define a displacement reaction with a suitable example.

State how displacement reaction represented.

Give a reason why zinc displaces hydrogen from dilute sulphuric acid but copper does not.

Explain the term double decomposition precipitation reaction.

Give a balanced equation for the preparation of two different insoluble lead salts from their salt solutions by double decomposition precipitation.

Explain with the help of balanced equations, how precipitation reactions are used for identifying the positive radicals in three different salts, each having a different cation [positive ion].

Define the term – double decomposition – neutralization reaction.

State the double decomposition – neutralization reaction with a suitable representation.

Convert an insoluble base

Convert a soluble base to their respective soluble salts by neutralization reaction.

Explain the term energy changes in a chemical change or reaction.

Give an example with a balanced equation, of the following reaction:

exothermic reaction

Give an example with a balanced equation, of the following reaction:

endothermic reaction

Give an example with a balanced equation, of the following reaction:

photochemical reaction

Give an example with a balanced equation, of the following reaction:

electrochemical reaction

Supply of energy may be required to initiate a reaction. State the different forms with a suitable example of reactions initiated by the supply of energy.

Chemical Changes & Reactions

### Viraf J. Dalal solutions for Class 9 Simplified ICSE Chemistry Chapter 2 Chemical Changes & Reactions Chemical Changes & Reactions

Chemical Changes & Reactions | Q 1.1

Complete the statement by filling in the blank with the correct word:

Direct combination reaction of sulphur dioxide with water gives ________.

• $\ce{H2SO4}$

• $\ce{H2SO3}$

• $\ce{H2S2O7}$

Chemical Changes & Reactions | Q 1.2

Complete the statement by filling in the blank with the correct word:

Formation of hydrogen chloride from hydrogen and chlorine is an example of __________.

• photochemical reaction

• electrochemical reaction

Chemical Changes & Reactions | Q 1.3

Complete the statement by filling in the blank with the correct word:

The reaction of hydrogen burning in oxygen to give a neutral liquid is an example of ________ reaction.

• exothermic

• endothermic

Chemical Changes & Reactions | Q 1.4

Complete the statement by filling in the blank with the correct word:

The neutral gas evolved when lead nitrate undergoes thermal decomposition is _________.

• nitrogen dioxide

• oxygen

• nitrogen

Chemical Changes & Reactions | Q 1.5

Complete the statement by filling in the blank with the correct word:

The reddish-brown precipitate obtained during a double decomposition precipitation reaction between an iron salt and alkali is __________.

• iron [II] hydroxide

• iron [III] hydroxide

Chemical Changes & Reactions | Q 2.1

Select the correct answer from the options given below:

State the gaseous product formed, when

An active metal reacts with dilute sulphuric acid.

• Ammonia

• Hydrogen chloride

• Hydrogen

• Nitrogen dioxide

• Nitric oxide

Chemical Changes & Reactions | Q 2.2

Select the correct answer from the options given below:

State the gaseous product formed, when

A metallic nitrate undergoes thermal decomposition giving a coloured gas.

• Ammonia

• Hydrogen chloride

• Hydrogen

• Nitrogen dioxide

• Nitric oxide

Chemical Changes & Reactions | Q 2.3

Select the correct answer from the options given below:

State the gaseous product formed, when

Two gases one of them neutral combines by absorption of light energy.

• Ammonia

• Hydrogen chloride

• Hydrogen

• Nitrogen dioxide

• Nitric oxide

Chemical Changes & Reactions | Q 2.4

Select the correct answer from the options given below:

State the gaseous product formed, when

An ammonium salt reacts with an alkali.

• Ammonia

• Hydrogen chloride

• Hydrogen

• Nitrogen dioxide

• Nitric oxide

Chemical Changes & Reactions | Q 2.5

Select the correct answer from the options given below:

State the gaseous product formed, when

An exothermic reaction takes place between ammonia and neutral gas.

• Ammonia

• Hydrogen chloride

• Hydrogen

• Nitrogen dioxide

• Nitric oxide

Chemical Changes & Reactions | Q 3.1

Give a balanced equation for the following type of reaction:

A direct combination reaction between phosphorus and neutral gas.

Chemical Changes & Reactions | Q 3.2

Give a balanced equation for the following type of reaction:

A soluble salt of lead formed from an insoluble base by double decomposition – neutralization.

Chemical Changes & Reactions | Q 3.3

Give a balanced equation for the following type of reaction:

A thermal decomposition reaction of a salt – which results in the formation of nitrogen gas.

Chemical Changes & Reactions | Q 3.4

Give a balanced equation for the following type of reaction:

A synthesis reaction between a metal and a non-metal resulting in the formation of an insoluble salt of iron.

Chemical Changes & Reactions | Q 3.5

Give a balanced equation for the following type of reaction:

A decomposition reaction of a salt which leaves behind a silvery metal.

Chemical Changes & Reactions | Q 4.1

Differentiate between the following:

Synthesis reaction and a substitution reaction.

Chemical Changes & Reactions | Q 4.2

Differentiate between the following:

Electrolytic decomposition and photochemical decomposition.

Chemical Changes & Reactions | Q 4.3

Differentiate between the following:

Thermal decomposition & thermal dissociation.

Chemical Changes & Reactions | Q 4.4

Differentiate between the following:

Decomposition reaction and a double decomposition reaction.

Chemical Changes & Reactions | Q 4.5

Differentiate between the following:

Neutralization reaction and a precipitation reaction.

Chemical Changes & Reactions | Q 5

Match the chemical reactions in List I with the appropriate answer in List II.

 List I List II 1. $\ce{AB⇌[heat]A + B}$ A: Double decomposition 2. $\ce{AB->A + B}$ B: Thermal dissociation 3. $\ce{X+Y- + AB+B- ->X+B- + A+Y-}$ C: Endothermic reaction 4. $\ce{X + YZ->XZ + Y}$ D: Displacement reaction 5. $\ce{X + Y->[heat]XY - \Delta}$ E: Decomposition reaction
Chemical Changes & Reactions | Q 6.1

Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.

Copper nitrate.

Chemical Changes & Reactions | Q 6.2

Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.

Ammonium dichromate.

Chemical Changes & Reactions | Q 6.3

Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.

Zinc carbonate.

Chemical Changes & Reactions | Q 6.4

Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.

Chemical Changes & Reactions | Q 6.5

Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.

Calcium hydroxide.

## Viraf J. Dalal solutions for Class 9 Simplified ICSE Chemistry chapter 2 - Chemical Changes & Reactions

Viraf J. Dalal solutions for Class 9 Simplified ICSE Chemistry chapter 2 (Chemical Changes & 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 Class 9 Simplified ICSE Chemistry solutions in a manner that help students grasp basic concepts better and faster.

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Concepts covered in Class 9 Simplified ICSE Chemistry chapter 2 Chemical Changes & Reactions are Classification of Change: Chemical Changes, Conditions Necessary for Chemical Reactions, Types of Chemical Change or Chemical Reaction, Direct Combination (or Synthesis) Reaction, Decomposition Reactions, Single Displacement Reactions, Double Displacement Reaction, Energy Change in Chemical Reactions, Chemical Reaction.

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