Class 10 Science Chemical Reactions and Equations questions

Q 1 :

Which of the following is NOT a type of chemical reaction?

Combination reaction
Decomposition reaction
Condensation reaction
Displacement reaction

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(3) Condensation reaction

Q 2 :

What is observed when quicklime (CaO) is added to water?

No reaction occurs
Bubbles are formed
A highly exothermic reaction takes place
A gas is evolved

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(3) A highly exothermic reaction takes place

Q 3 :

Which gas is released when hydrochloric acid reacts with zinc?

Oxygen
Hydrogen
Carbon dioxide
Nitrogen

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(2) Hydrogen

Q 4 :

What is the color change observed when iron nails are placed in copper sulfate solution?

No color change
The solution turns blue
The solution turns green
The solution turns colorless

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(3) The solution turns green

Q 5 :

Which of the following statements is true about a redox reaction?

Both oxidation and reduction occur simultaneously
Only oxidation occurs
Only reduction occurs
Neither oxidation nor reduction occurs

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(1) Both oxidation and reduction occur simultaneously

Q 6 :

Which of the following reactions is an endothermic reaction?

Burning of coal.
Decomposition of vegetable matter into compost.
Process of respiration.
Decomposition of calcium carbonate to form quick lime and carbon dioxide.

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(2)

Decomposition of calcium carbonate to form quick lime and carbon dioxide is an endothermic reaction since this process absorbs heat from atmosphere.

Q 7 :

Zn + HCl $\to$ Zn + _______

$H_{2}$
$C l_{2}$
Zn
None of these

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(1)

Zn + HCl $\to$ Zn $C l_{2} + H_{2}$
Displacement reaction is a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reactions.

Q 8 :

Which among the following statement(s) is (are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to:

(i) The formation of silver by decomposition of silver chloride.
(ii) Sublimation of silver chloride.
(iii) Decomposition of chlorine gas from silver chloride.
(iv) Oxidation of silver chloride.

(i) only
(i) and (iii)
(ii) and (iii)
(iv) only

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(1)

Exposure of silver chloride to sunlight for a long duration turns silver chloride grey due to the photolysis reaction in which the decomposition of silver chloride takes place in the presence of sunlight, leading to the formation of silver.

Q 9 :

The reaction which decomposes after the supply of heat is called ______.

Thermal decomposition
Combination reaction
Redox reaction
Displacement reaction

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(1)

A thermal decomposition reaction occurs when heat is applied to a compound causing it to decompose (break down) into multiple different chemical substances. An example is when baking soda (sodium bicarbonate) is heated:

$2 N a H C O_{3} (s) \to C O_{2} (g) + H_{2} O (g) + N a_{2} C O_{3} (s)$

Q 10 :

In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution:

(i) exchange of atoms takes place.
(ii) exchange of ions takes place.
(iii) a precipitate is produced.
(iv) an insoluble salt is produced.

The correct option is:

(ii) and (iv)
(i) and (iii)
only (ii)
(ii), (iii) and (iv)

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(4)

In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution, sodium sulphate chemically reacts with barium chloride in the form of their aqueous solution to form an insoluble white precipitate of barium sulphate and sodium chloride.

$N a_{2} S O_{4} (a q) + B a C l_{2} (a q) \to B a S O_{4} (s) ↓ + 2 N a C l (a q)$
(insoluble)

Here, exchange of ions takes place.

Q 11 :

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is _____.

1 : 1
2 : 1
4 : 1
1 : 2

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(2)

The mole ratio of hydrogen and oxygen gases liberated during the electrolysis of water is 2 : 1. Since two atoms of hydrogen and one atom of oxygen are present in the water molecule respectively:

$2 H_{2} O \to 2 H_{2} + O_{2}$

Q 12 :

Which of the following is an example of simple displacement?

the electrolysis of water
the burning of methane
the reaction of a metal with an acid
the reaction of two salt solutions to form a precipitate

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(3)

The displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule. For instance, when iron is added to a copper sulphate solution, it displaces the copper metal.

A + B - C $\to$ A - C + B

Q 13 :

Which law should be kept in mind while we balance chemical equations?

Conservation of momentum
Conservation of mass
Conservation of energy
Conservation of frequency

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(2)

The law of conservation of mass states that “mass can neither be created nor destroyed.” So, both the sides of the chemical reactions have to be balanced to ensure that this law is followed and thus the number of the reactant and the product molecules remains the same on both sides of the equation.

Q 14 :

In which of the following, the identity of initial substance remains unchanged?

Curdling of milk
Formation of crystals by process of crystallisation
Fermentation of grapes
Digestion of food

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(2)

Formation of crystals by process of crystallisation is the reaction in which the original identity of the substance remains as such, since on heating the crystals they can again be converted in the powder form and again on cooling they can recrystallise.

Q 15 :

Which one of the following processes involves a chemical reaction?

Liquification of air
Heating copper wire in presence of air at high temperature
Keeping petrol in a china dish in the open
Storing of oxygen gas under pressure in a gas cylinder

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(2)

A physical change is the one in which the chemical properties of a substance do not change.
No chemical change is observed when we store oxygen gas under pressure, or during liquefaction of air, or when petrol is kept open in a china dish.
However, when we heat a copper wire in the presence of air, copper oxide is formed.

The reaction is as follows: $\underset{c o p p e r}{2 C u (s)} + \underset{o x y g e n}{O_{2} (g)} \overset{H e a t}{\to} \underset{c c o p p e r (i i) o x i d e}{2 C u O (s)}$

Thus, heating of copper wire in presence of air at high temperature is an example of a chemical reaction.

Q 16 :

In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?

$2 H_{2} (I) + O_{2} (I) \to 2 H_{2} O (g)$
$2 H_{2} (I) + O_{2} (I) \to 2 H_{2} O (I)$
$2 H_{2} (g) + O_{2} (g) \to 2 H_{2} O (I)$
$2 H_{2} (g) + O_{2} (g) \to 2 H_{2} O (g)$

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(3)

Hydrogen and oxygen occur in the gaseous state in nature, whereas when they combine to form water, the physical state of the matter converts to the liquid state.

Q 17 :

Which one of the following precipitates are formed when the carbon dioxide gas is passed through lime water?

$C a {(O H)}_{2}$
$C a {(O H)}_{4}$
$C a C O_{3}$
$C a C O_{2}$

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(3)

When carbon dioxide is passed through lime water, it turns milky due to the formation of white precipitate of calcium carbonate.

$C a {(O H)}_{2} + C O_{2} \to C a C O_{3} + H_{2} O$

Q 18 :

The following reaction is an example of a:

$4 N H_{3} (g) + 5 O_{2} (g) ⟶ 4 N O (g) + 6 H_{2} O (g)$

(i) Displacement reaction
(ii) Combination reaction
(iii) Redox reaction
(iv) Neutralisation reaction

(i) and (iv)
(ii) and (iii)
(i) and (iii)
(iii) and (iv)

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(3)

The given reaction is an example of displacement and redox reaction since oxygen replaces hydrogen from the ammonia molecule leading to the formation of NO. Similarly, $O_{2}$ is getting reduced in the reaction and ammonia is getting oxidised. Thus, a redox reaction takes place in this case. reaction.
Therefore, the below reaction is both the displacement and the redox reaction.
$4 N H_{3} (g) + 5 O_{2} (g) ⟶ 4 N O (g) + 6 H_{2} O (g)$

Q 19 :

What does the symbol " $↓$ " represent in a chemical reaction?

Gas released
Solid state
Precipitate formed
Direction of reaction

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(3)

The downward arrow symbol " $↓$ " represents the formation of the precipitate in a chemical reaction.

Q 20 :

Which of the following reaction is not feasible?

Aluminium + Copper sulphate
Zinc + Copper sulphate solution
Iron + Zinc sulphate solution
Copper + Zinc sulphate

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(4)

Copper + Zinc sulphate is not the feasible reaction since zinc is more reactive than copper and copper cannot displace it from its salt solution as per the reactivity series of metals

Q 21 :

A dilute ferrous sulphate solution was gradually added to the beaker containing acidified potassium permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?

$K M n O_{4}$ is an oxidising agent, it oxidises $F e S O_{4}$ .
$F e S O_{4}$ acts as an oxidising agent and oxidises $K M n O_{4}$
The colour disappears due to dilution; no reaction is involved
$K M n O_{4}$ is an unstable compound and decomposes in presence of $F e S O_{4}$ to a colourless compound

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(1)

In this reaction, potassium permanganate $(K M n O_{4})$ is an oxidising agent. It oxidises ferrous sulphate to ferric sulphate in the presence of dilute $H_{2} S O_{4}$

$2 K M n O_{4} + 10 F e S O_{4} + 8 H_{2} S O_{4} \to K_{2} S O_{4} + 2 M n S O_{4} + 5 F e_{2} {(S O_{4})}_{3} + 8 H_{2} O$

The solution is coloured purple because of the KMnO?, and it eventually disappears when all the KMnO? in the solution is used.:

Q 22 :

Which of the following gases can be used for storage of fresh sample of an oil for a long time?

Carbon dioxide
Nitrogen
Hydrogen
Helium

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(4)

Helium can be used to store the fresh samples of an oil for a long time since it is an inert gas and will not react with the sample of the food, keeping its quality intact as such.

Q 23 :

Shashank was asked to carry out a displacement reaction which would show the following:

(i) Formation of colourless solution
(ii) Black deposits

The reactants he should use are:

Fe(s) and $A l_{2} {(S O_{4})}_{3}$ (aq)
Al(s) and $F e S O_{4}$ (aq)
$Z n (s) a n d C u S O_{4} (a q)$
$F e (s) a n d Z n S O_{4} (a q)$

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(2)

When aluminium metal is added to ferrous sulphate $(F e S O_{4})$ solution, the green colour of ferrous sulphate solution disappears and a colourless solution is formed due to the formation of aluminium sulphate solution, and greyish-black iron gets deposited.

$\underset{G r e e n s o l u t i o n}{3 F e S O_{4}} (a q) + 2 A l (s) ⟶ \underset{G r e y i s h b l a c k d e p o s i t}{3 F e (s)} + \underset{C o l o u r l e s s s o l u t i o n}{A l_{2} {(S O_{4} )}_{3} (a q)}$

Q 24 :

The oxidation reaction which produces heat and light is called:

Endothermic
Photochemical
Exothermic
Combustion

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(4)

A combustion reaction is a kind of chemical reaction in which a reaction between any combustible substance and an oxidiser takes place in order to form an oxidised product accompanied by the evolution of heat and light during the reaction.

Q 25 :

Heating of ferrous sulphate is a type of:

Decomposition reaction
Combination reaction
Displacement reaction
All of the above

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(1)

A decomposition reaction is a reaction in which a compound breaks down into two or more simpler substances. Most decomposition reactions require an input of energy in the form of heat, light, or electricity.

The heating of ferrous sulphate is a decomposition and an endothermic reaction because it involves absorption of heat to form ferric oxide $(F e_{2} O_{3})$ , sulphur dioxide ( $S O_{2}$ ), and sulphur trioxide $(S O_{3})$ .

The equation for this reaction can be written as:
$2 F e S O_{4} (s) \overset{h e a t}{\to} F e_{2} O_{3} (s) + S O_{2} (g) + S O_{3} (g)$

Q 26 :

To balance $A l {(O H)}_{3} + H N O_{3} ⟶ A l {(N O_{3})}_{3} + H_{2} O$ , number of $H N O_{3}$ molecules required will be:

2
4
3
8

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(3)

Three molecules of $H N O_{3}$ are required to balance the given chemical reaction and to satisfy the law of conservation of mass.

$A l {(O H)}_{3} + 3 H N O_{3} ⟶ A l {(N O_{3})}_{3} + 3 H_{2} O$

Q 27 :

Which metal is displaced when lead is put in the solution of copper chloride?

Lead
Copper
Chlorine
All of these

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(2)

Copper will be displaced from the solution since it is less reactive than lead. Lead will displace copper from its salt solution because it is more reactive than copper.

Q 28 :

What is the name of the process where fatty foods become rancid?

Corrosion
Oxidation
Reduction
Hydrogenation

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(2)

Fatty foods become rancid due to the process of oxidation. Food turns rancid when the fats and oils within them get oxidised and the taste and smell of the food changes. It is produced by aerial oxidation of unsaturated fat present in foods and other products, marked by unpleasant odour or flavour.

Q 29 :

Rancidity can be prevented by:

adding antioxidants
storing food away from light
keeping food in refrigerator
all of the above

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(4)

Rancidity can be prevented by packing fat- and oil-containing foods in nitrogen gas. It can be retarded by keeping food in a refrigerator. It can also be retarded by storing food in air-tight containers and away from light in order to prevent their decomposition

Topic Question Set

Q 1 :

Which of the following is NOT a type of chemical reaction?

Q 2 :

What is observed when quicklime (CaO) is added to water?

Q 3 :

Which gas is released when hydrochloric acid reacts with zinc?

Q 4 :

What is the color change observed when iron nails are placed in copper sulfate solution?

Q 5 :

Which of the following statements is true about a redox reaction?

Q 6 :

Which of the following reactions is an endothermic reaction?

Q 7 :

Zn + HCl $\to$ Zn + _______

Q 9 :

The reaction which decomposes after the supply of heat is called ______.

Q 10 :

In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution:

(i) exchange of atoms takes place.
(ii) exchange of ions takes place.
(iii) a precipitate is produced.
(iv) an insoluble salt is produced.

The correct option is:

Q 11 :

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is _____.

Q 12 :

Which of the following is an example of simple displacement?

Q 13 :

Which law should be kept in mind while we balance chemical equations?

Q 14 :

In which of the following, the identity of initial substance remains unchanged?

Q 15 :

Which one of the following processes involves a chemical reaction?

Q 16 :

In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?

Q 17 :

Which one of the following precipitates are formed when the carbon dioxide gas is passed through lime water?

Q 18 :

The following reaction is an example of a:

$4 N H_{3} (g) + 5 O_{2} (g) ⟶ 4 N O (g) + 6 H_{2} O (g)$

(i) Displacement reaction
(ii) Combination reaction
(iii) Redox reaction
(iv) Neutralisation reaction

Q 19 :

What does the symbol " $↓$ " represent in a chemical reaction?

Q 20 :

Which of the following reaction is not feasible?

Q 21 :

A dilute ferrous sulphate solution was gradually added to the beaker containing acidified potassium permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?

Q 22 :

Which of the following gases can be used for storage of fresh sample of an oil for a long time?

Q 23 :

Shashank was asked to carry out a displacement reaction which would show the following:

(i) Formation of colourless solution
(ii) Black deposits

The reactants he should use are:

Q 24 :

The oxidation reaction which produces heat and light is called:

Q 25 :

Heating of ferrous sulphate is a type of:

Q 26 :

To balance $A l {(O H)}_{3} + H N O_{3} ⟶ A l {(N O_{3})}_{3} + H_{2} O$ , number of $H N O_{3}$ molecules required will be:

Q 27 :

Which metal is displaced when lead is put in the solution of copper chloride?

Q 28 :

What is the name of the process where fatty foods become rancid?

Q 29 :

Rancidity can be prevented by:

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Topic Question Set

Q 1 : Which of the following is NOT a type of chemical reaction?

Q 2 : What is observed when quicklime (CaO) is added to water?

Q 3 : Which gas is released when hydrochloric acid reacts with zinc?

Q 4 : What is the color change observed when iron nails are placed in copper sulfate solution?

Q 5 : Which of the following statements is true about a redox reaction?

Q 6 : Which of the following reactions is an endothermic reaction?

Q 7 : Zn + HCl → Zn + _______

Q 9 : The reaction which decomposes after the supply of heat is called ______.

Q 10 : In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution: (i) exchange of atoms takes place. (ii) exchange of ions takes place. (iii) a precipitate is produced. (iv) an insoluble salt is produced. The correct option is:

Q 11 : Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is _____.

Q 12 : Which of the following is an example of simple displacement?

Q 13 : Which law should be kept in mind while we balance chemical equations?

Q 14 : In which of the following, the identity of initial substance remains unchanged?

Q 15 : Which one of the following processes involves a chemical reaction?

Q 16 : In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?

Q 17 : Which one of the following precipitates are formed when the carbon dioxide gas is passed through lime water?

Q 18 : The following reaction is an example of a: 4NH3​(g)+5O2(g)⟶4NO(g)+6H2O(g) (i) Displacement reaction (ii) Combination reaction (iii) Redox reaction (iv) Neutralisation reaction

Q 19 : What does the symbol "↓" represent in a chemical reaction?

Q 20 : Which of the following reaction is not feasible?

Q 21 : A dilute ferrous sulphate solution was gradually added to the beaker containing acidified potassium permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?

Q 22 : Which of the following gases can be used for storage of fresh sample of an oil for a long time?

Q 23 : Shashank was asked to carry out a displacement reaction which would show the following: (i) Formation of colourless solution (ii) Black deposits The reactants he should use are:

Q 24 : The oxidation reaction which produces heat and light is called:

Q 25 : Heating of ferrous sulphate is a type of:

Q 26 : To balance Al(OH)3 + HNO3 ⟶ Al(NO3)3 + H2O, number of HNO3 molecules required will be:

Q 27 : Which metal is displaced when lead is put in the solution of copper chloride?

Q 28 : What is the name of the process where fatty foods become rancid?

Q 29 : Rancidity can be prevented by:

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Q 1 :

Which of the following is NOT a type of chemical reaction?

Q 2 :

What is observed when quicklime (CaO) is added to water?

Q 3 :

Which gas is released when hydrochloric acid reacts with zinc?

Q 4 :

What is the color change observed when iron nails are placed in copper sulfate solution?

Q 5 :

Which of the following statements is true about a redox reaction?

Q 6 :

Which of the following reactions is an endothermic reaction?

Q 7 :

Zn + HCl $\to$ Zn + _______

Q 9 :

The reaction which decomposes after the supply of heat is called ______.

Q 10 :

In a double displacement reaction such as the reaction between sodium sulphate solution and barium chloride solution:

(i) exchange of atoms takes place.
(ii) exchange of ions takes place.
(iii) a precipitate is produced.
(iv) an insoluble salt is produced.

The correct option is:

Q 11 :

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is _____.

Q 12 :

Which of the following is an example of simple displacement?

Q 13 :

Which law should be kept in mind while we balance chemical equations?

Q 14 :

In which of the following, the identity of initial substance remains unchanged?

Q 15 :

Which one of the following processes involves a chemical reaction?

Q 16 :

In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?

Q 17 :

Which one of the following precipitates are formed when the carbon dioxide gas is passed through lime water?

Q 18 :

The following reaction is an example of a:

$4 N H_{3} (g) + 5 O_{2} (g) ⟶ 4 N O (g) + 6 H_{2} O (g)$

(i) Displacement reaction
(ii) Combination reaction
(iii) Redox reaction
(iv) Neutralisation reaction

Q 19 :

What does the symbol " $↓$ " represent in a chemical reaction?

Q 20 :

Which of the following reaction is not feasible?

Q 21 :

A dilute ferrous sulphate solution was gradually added to the beaker containing acidified potassium permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?

Q 22 :

Which of the following gases can be used for storage of fresh sample of an oil for a long time?

Q 23 :

Shashank was asked to carry out a displacement reaction which would show the following:

(i) Formation of colourless solution
(ii) Black deposits

The reactants he should use are:

Q 24 :

The oxidation reaction which produces heat and light is called:

Q 25 :

Heating of ferrous sulphate is a type of:

Q 26 :

To balance $A l {(O H)}_{3} + H N O_{3} ⟶ A l {(N O_{3})}_{3} + H_{2} O$ , number of $H N O_{3}$ molecules required will be:

Q 27 :

Which metal is displaced when lead is put in the solution of copper chloride?

Q 28 :

What is the name of the process where fatty foods become rancid?

Q 29 :

Rancidity can be prevented by: