MCQ Questions for Class 10 Chemistry Chemical Reactions And Equations Quiz 2

Which of the following is/are combination reaction(s)?
(i)

$2KClO_{3} \overset{Heat}{\rightarrow} 2KCl + 3O_{2}$
(ii)

$MgO + H_{2}O \rightarrow Mg(OH)_{2}$
(iii)

$4Al + 3O_{2} \rightarrow 2Al_{2} O_{3}$
(iv)

$Zn + FeSO_{4} \rightarrow ZnSO_{4} + Fe$

0%
(i) and (iii)
0%
(iii) and (iv)
0%
(ii) and (iv)
0%
(ii) and (iii)

Explanation

Option (i) is a decomposition reaction.

Option (ii) is a combination reaction as magnesium oxide

$(MgO)$ and water combines to form magnesium hydroxide

$(Mg(OH)_{2})$ .

Option (iii) is again a combination reaction as aluminium

$(Al)$ combines with oxygen

$(O_{2})$ to form aluminium oxide

$(Al_{2}O_{3})$ .

Option (iv) is a displacement reaction.

The correct answer is option

$D$ .

Which among the following is(are) double displacement reaction(s)?
(i)

$Pb+CuCl_{2} \rightarrow PbCl_{2}+ Cu$
(ii)

$Na_{2}SO_{4} + BaCl_{2} \rightarrow BaSO_{4} + 2NaCl$
(iii)

$C + O_{2} \rightarrow CO_{2}$
(iv)

$CH_{4} + 2O_{2} \rightarrow CO_{2} + 2H_{2}O$

0%
(i) and (iv)
0%
(ii) only
0%
(i) and (ii)
0%
(iii) and (iv)

Explanation

Correct option is (ii)

$\text{Explanation for correct option}$

(ii)

$Na^{+}$ ion from

$Na_2SO_4$ combines with

$Cl^{-}$ ion of

$BaCl_2$ and

$SO_4^{2-}$ SO42− ion combines with

$Ba^{+}$ ion to form two new compounds as sodium chloride

$(NaCl)$ and barium sulphate

$(BaSO_4)$ respectively.

Hence, it is a displacement reaction.

$\text{Explanation for incorrect option}$

(i) This reaction is a displacement reaction, in which

$Pb$ , being more reactive than

$Cu$ , displaces

$Cu$ from

$CuCl_2$ to form

$PbCl_2$ .

(iii) This is a combination reaction, in which carbon

$(C)$ and oxygen

$(O)$ combine to form a carbon dioxide

$(CO_2)$ .

(iv) It is a redox reaction.

$\bullet$ In this reaction, carbon loses hydrogen and forms carbon dioxide

$(CH_4\rightarrow CO_2)$ .

$\bullet$ As a result, carbon is oxidised, while oxygen gains hydrogen and is reduced

$(O_2\rightarrow H_2O)$ .

$\bullet$ Hence, it is a redox reaction since both oxidation and reduction are occurring at the same time.

Which of the following statements about the given reaction is/are correct?

$3Fe(s) + 4H_{2}O(g) \rightarrow Fe_{3}O_{4}(s) + 4H_{2}(g)$
(i) Iron metal is getting oxidised.
(ii) Water is getting reduced.
(iii) Water is acting as reducing agent.
(iv) Water is acting as oxidising agent.

0%
(i), (ii) and (iii)
0%
(iii) and (iv)
0%
(i), (ii) and (iv)
0%
(ii) and (iv)

Explanation

Option (i) is correct as iron (Fe) is combining with oxygen to form iron oxide (

$Fe_3O_4=Fe^{II}O.{ Fe^{III} }_{ 2 }{ O }_{ 3 }$ ).
Iron is oxidising from 0 to +2 and +3 state.

Option (ii) is correct as water (

$H_{2}O$ ) is being reduced by removal of oxygen to form hydrogen (

$H_{2}$ ) gas.

Option (iv) is correct as water (

$H_{2}O$ ) itself is being reduced and is oxidising Iron(Fe), thereby acting as an oxidising agent.

Option C is correct.

Silver articles become black on prolonged exposure to air.

This is due to the formation of :

0%
$Ag_{3}N$
0%
$Ag_{2}O$
0%
$Ag_{2}S$
0%
$Ag_{2}S$ and $Ag_{3}N$

Explanation

Silver metal is highly unreactive, i.e., it does not react with oxygen.

But with prolonged exposure to air, it reacts with hydrogen sulphide gas (

$H_2S$ ).

Silver articles form a coating of silver sulphide (

$Ag_2S$ ) and lose their shine (get tarnished).

If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of:

0%
$CuSO_{4}$
0%
$CuCO_{3}$
0%
$Cu(NO_{3})_{2}$
0%
$CuO$

On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained. What other name can be given to this precipitation reaction?

0%
Synthesis reaction
0%
Double displacement reaction
0%
Combination reaction
0%
Decomposition reaction

Explanation

Barium chloride (

$BaCl_{2}$ ) reacts with sodium sulphite (

$Na_{2}SO_{3}$ ) to form barium sulphite (

$BaSO_{3}$ ) and sodium chloride (NaCl).

$BaCl_{2}(aq) + Na_{2}SO_{3}(aq) \rightarrow BaSO_{3}(s) + 2NaCl(aq)$
(white ppt)

The above precipitation reaction is also a double displacement reaction as both reactants exchange their ions to form new products.

Ferrous sulphate decomposes with the evolution of a gas having a characteristic odour of burning sulphur. Identify the type of reaction.

0%
Combination reaction
0%
Displacement reaction
0%
Double displacement reaction
0%
Thermal decomposition reaction

Explanation

Ferrous sulphate on heating decomposes to produce the ferric oxide, sulphur dioxide and sulphur trioxide.

The balanced equation for this thermal decomposition reaction can be written as:

$2FeSO_{4}(s) \overset{heat}{\rightarrow} Fe_{2}O_{3}(s) + SO_{2}(g) + SO_{3}(g)$

Identify the type of chemical reaction.

$TiCl_{4}(l) + Mg(s) \rightarrow Ti(s) + MgCl_{2}(s)$

0%
Synthesis reaction
0%
Displacement reaction
0%
Precipitation reaction
0%
None of these

Explanation

Titanium tetrachloride (

$TiCl_{4}$ ) reacts with magnesium

$(Mg)$ to form titanium

$(Ti)$ and magnesium chloride(

$MgCl_{2}$ ). It is a displacement reaction, as the more active magnesium displaces titanium in titanium chloride. The balanced equation can be written as:

$TiCl_{4}(l) + 2Mg(s) \rightarrow Ti(s) + 2MgCl_{2}(s)$

Complete the missing components/variables given as

$x$ in the following reactions:

$CaCO_{3}(s) \xrightarrow{x} CaO(s) + CO_{2}(g)$

0%
$x = Heat$
0%
$x = Catalyst$
0%
$x = O_{2}$
0%
None of these

Explanation

Calcium carbonate on heating decomposes to form calcium oxide(quick lime) and carbon dioxide. The equation for this thermal decomposition reaction can be written as:

$CaCO_{3} \overset{heat}{\rightarrow} CaO + CO_{2}$
Therefore,

$x$ in the above reaction is heat.

$HgO(s) \xrightarrow{Heat} Hg(l) + O_{2}(g)$
The above given reaction is:

0%
combustion reaction
0%
displacement reaction
0%
thermal decomposition reaction
0%
photolytic decomposition reaction

Explanation

Mercuric oxide (

$HgO$ ) decomposes on heating to give mercury (

$Hg$ ) and oxygen (

$O_{2}$ ). It is a thermal decomposition reaction and the balanced equation can be written as:

$2HgO(s) \overset{heat}{\rightarrow} 2Hg(l) + O_{2}(g)$

Identify the type of chemical reaction.

$Mg(s) + Cl_{2}(g) \rightarrow MgCl_{2}(s)$

0%
Decomposition reactions
0%
Combination reaction
0%
Displacement reaction
0%
Double displacement reaction

Explanation

Magnesium (

$Mg$ ) combines with chlorine (

$Cl_{2}$ ) to form a new product as magnesium chloride (

$MgCl_{2}$ ). Therefore it is a combination reaction and the balanced equation can be written as:

$Mg(s) + Cl_{2}(g) \rightarrow MgCl_{2}(s)$

Write the balanced equation for the reaction for the following statement:

Mg burns in presence of air.

0%
$Mg(s)+O_2(g) \rightarrow MgO_{2}(s)$
0%
$2Mg(s)+2O(g) \rightarrow 2MgO(s)$
0%
$2Mg(s)+O_2(g) \rightarrow 2MgO(s)$
0%
$Mg(s)+O_2(g) \rightarrow MgO(s)$

Explanation

When

$Mg$ burns with oxygen gas, it undergoes the process of oxidation, and magnesium oxide is formed.

Balanced equation is:

$2Mg(s)+O_2(g) \rightarrow 2MgO(s)$

Which of the following oxide(s) of iron would be obtained on prolonged reaction of iron with steam?

0%
$FeO$
0%
$Fe_2O_3$
0%
$Fe_3O_4$
0%
$Fe_2O_3$ and $Fe_3O_4$

Explanation

On prolonged heating with steam Fe produces

$Fe_3O_4$ and release hydrogen gas. It is a mixed oxide of Fe.

$3Fe+ 4H_2O \rightarrow Fe_3O_4(s) + 4H_2(g)$

Write the balanced chemical equations for the following reactions:

Sodium hydrogen carbonate on reaction with hydrochloric acid gives sodium chloride, water and liberates carbon dioxide.

0%
$NaHCO_{3} + 2HCl \rightarrow NaCl + 2H_{2}O + CO_{2}$
0%
$2NaHCO_{3} + HCl \rightarrow NaCl + H_{2}O + 2CO_{2}$
0%
$NaHCO_{3} + HCl \rightarrow NaCl + H_{2}O + CO_{2}$
0%
$2NaHCO_{3} + HCl \rightarrow 2NaCl + H_{2}O + CO_{2}$

Explanation

$NaHCO_3+HCl\longrightarrow NaCl+H_2O+CO_2$

	No. of Atom	No. of Atom
$Na$	$1$	$1$
$H$	$2$	$2$
$C$	$1$	$1$
$Cl$	$1$	$1$
$O$	$3$	$3$

What type of chemical reaction does the reaction belong to?

A piece of sodium metal is added to absolute ethanol to form sodium ethoxide and hydrogen gas.

0%
Precipitation Reactions
0%
Neutralization Reactions
0%
Decomposition Reactions
0%
Displacement Reactions

Explanation

Sodium metal

$(Na)$ reacts with ethanol (

$C_{2}H_{5}OH$ ) to produce sodium ethoxide (

$C_{2}H_{5}ONa$ ) and hydrogen (

$H_{2}$ ). It is a displacement reaction in which the more active sodium displaces hydrogen in ethanol. The equation can be written as:

$2Na + 2C_{2}H_{5}OH \rightarrow 2C_{2}H_{5}ONa + H_{2}$

During the reaction of some metals with dilute hydrochloric acid, the following observations were made.

The reaction of sodium metal is found to be highly explosive because:

0%
Heat is evolved
0%
Due to the catalyst
0%
It is an endothermic reaction
0%
It is an exothermic reaction

Explanation

The reaction of sodium with hydrochloric acid is highly exothermic and therefore explosive in nature. Heat is evolved in an exothermic reaction.

$2Na(s) + 2HCl(aq) \longrightarrow 2NaCl(aq) + H_{2}(g)\ + Heat$

Which of the following reactions is an example of endothermic reaction?

0%
Burning of a candle
0%
Freezing of water into ice cubes
0%
Evaporation of liquid water to form water vapour
0%
Acid-base neutralization reaction

A less reactive metal replaces a more reactive metal from its salt solution in water.

0%
True
0%
False

Explanation

A less reactive metal cannot replace a more reactive metal from its salt solution in water.
In the reactivity series of metals in an arrangement of metals in the order of their decreasing reactivities. A more reactive metal can displace a less reactive metal from a solution of its salt.
For example:-

$CuSO_4+Fe\rightarrow FeSO_4+Cu$

Which of the following is a decomposition reaction?

0%
$NaOH + HCl \rightarrow NaCl + H_{2}O$
0%
$NH_{4}CNO \rightarrow H_{2}N CO NH_{2}$
0%
$2KClO_{3} \rightarrow 2KCl + 3O_{2}$
0%
$H_{2} + I_{2} \rightarrow 2HI$

Identify the type of chemical reaction.

$CaO(s) + SiO_{2}(s) \rightarrow CaSiO_{3}(s)$

0%
Displacement reaction
0%
Decomposition reaction
0%
Reduction reaction
0%
Combination reaction

Explanation

Calcium oxide

$(CaO)$ combines with silicon dioxide (

$SiO_{2}$ ) to form a new product as calcium silicate (

$CaSiO_{3}$ ). This is a combination reaction.

Identify the type of chemical reaction.

$H_{2}O_{2}(l) \xrightarrow{U V} H_{2}O(l)+O_{2}(g)$

0%
Neutralization reaction
0%
Combination reaction
0%
Decomposition reaction
0%
Double Displacement reaction

Explanation

Hydrogen peroxide (

$H_{2}O_{2}$ ) decomposes in the presence of ultraviolet rays to give water (

$H_{2}O$ ) and oxygen (

$O_{2}$ ). The balanced equation for this decomposition reaction can be written as:

$2H_{2}O_{2}(l) \overset{UV}{\rightarrow} 2H_{2}O(l) + O_{2}(g)$

A chemical reaction in which heat is evolved is called a/an:

0%
exothermic reaction
0%
endothermic reaction
0%
combination reaction
0%
decomposition reaction

In which reaction do two compounds exchange their ions or radicals mutually to form two new compounds?

0%
Displacement reaction.
0%
Double displacement reaction.
0%
Synthesis reaction.
0%
Decomposition reaction.

Explanation

Those reactions in which two compounds react by an exchange of ions to form two new compounds are called double displacement reactions. In double replacement reactions, the positive ions and negative ions switch their positions and form two new compounds or products.

Example-

$KOH + HNO_3\rightarrow H_2O + KNO_3$

$Na_2S + 2HCl \rightarrow 2NaCl + H_2S$

Study the equation given below.

$2 Al+ (X) {H}_{2}{SO}_{4}\rightarrow Al_2({SO}_4)_{3}+{3H}_{2}$

In the given equation, what does

$X$ stand for?

0%
2
0%
3
0%
1
0%
5

Explanation

It is a displacement reaction in which Aluminium is a more reactive metal than hydrogen, so hydrogen is being displaced by aluminium.

$2Al$ +

$3H_2SO_4$

$\rightarrow$

$Al_2(SO_4)_3$ +

$3H_2$

$X$ stands for 3 and the correct answer is option B.

When calcium carbonate is heated, it decomposes to give ______________.

0%
water
0%
calcium oxide
0%
carbon dioxide
0%
calcium metal

Explanation

In presence of heat, calcium carbonate gets decomposes into calcium oxide and carbon dioxide.

Reaction:

$CaCO_3 \xrightarrow {\Delta} CaO+CO_2$

In a ____________reaction, two or more substances combine to a form a new single substance.

0%
decomposition
0%
combination
0%
displacement
0%
double displacement

Explanation

A combination reaction is a reaction in which two reactants combine to form one kind of product. For example,

$H_2+Cl_2 \rightarrow 2HCl$

Hence, option

$B$ is correct.

In the reaction,

$PbO + C \rightarrow Pb + CO$ :

0%
PbO is reduced
0%
C acts as a oxidizing agent
0%
PbO is oxidised
0%
This reaction does not represent redox reaction

Explanation

Here, carbon oxidizes itself to form

$CO_2$ and reduces PbO to form Pb. Therefore,

$C$ acts as a reducing agent. This is a redox reaction.

What happens when copper rod is dipped in iron sulphate solution?

0%
A lot of heat will be released
0%
The solution becomes blue in colour
0%
No reaction takes place
0%
The solution becomes pink in colour

Explanation

Iron is more reactive than copper. Hence,

$Cu$ will not displace iron from iron sulphate, hence, no reaction will take place.

The reaction between nitrogen and hydrogen to give ammonia is an example of :

0%
decomposition reaction
0%
combination reaction
0%
displacement reaction
0%
combustion reaction

Explanation

A combination reaction is a reaction in which two or more reactants combine to form a single product.

The reaction between hydrogen gas and nitrogen gsa to give ammonia is as follows.

$N_2 + 3H_2 \rightarrow 2NH_3$

Therefore, it is a combination reaction.

Option

$B$ is correct.

$Zn+H_2SO_4(dil)\rightarrow ZnSO_4+H_2\uparrow$

The above reaction is:

0%
decomposition reaction
0%
displacement reaction
0%
combination reaction
0%
synthesis reaction

CBSE Questions for Class 10 Chemistry Chemical Reactions And Equations Quiz 2 - MCQExams.com

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Practice Class 10 Chemistry Quiz Questions and Answers

CBSE Questions for Class 10 Chemistry Chemical Reactions And Equations Quiz 2 - MCQExams.com

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Practice Class 10 Chemistry Quiz Questions and Answers

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