MCQ Questions for Class 10 Chemistry Chemical Reactions And Equations Quiz 4

Write the balanced chemical reaction for the reaction of magnesium with hot water.

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$2Mg + 3H_2O \rightarrow 2MgOH + 3H_2$
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$Mg + 2H_2O \rightarrow Mg(OH)_2 + H_2$
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$2Mg + 3H_2O \rightarrow 3MgOH + 3H_2$
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$Mg + 3H_2O \rightarrow 2MgOH + 3H_2$

Explanation

Magnesium reacts with hot water to form magnesium hydroxide and hydrogen.

$Mg + 2H_2O \rightarrow Mg(OH)_2 + H_2$

Write a balanced chemical equation with state symbols for the following reaction:

When lithium hydroxide pellets are added to a solution of sulphuric acid, lithium sulphate and water are formed.

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LiOH(s) + 2H $_2$ SO $_4$ (aq) $\rightarrow$ Li $_2$ SO $_4$ (aq) + 2H $_2$ O(l)
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LiOH(s) + H $_2$ SO $_4$ (aq) $\rightarrow$ Li $_2$ SO $_4$ (aq) + H $_2$ O(l)
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2LiOH(s) + 2H $_2$ SO $_4$ (aq) $\rightarrow$ Li $_2$ SO $_4$ (aq) + 2H $_2$ O(l)
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2LiOH(s) + H $_2$ SO $_4$ (aq) $\rightarrow$ Li $_2$ SO $_4$ (aq) + 2H $_2$ O(l)

Explanation

For a balanced chemical reaction,

the number of atoms of particular element on left hand side should be equal to number of atoms of particular element on right hand side

so, balanced chemical equation is

$2LiOH + H_2SO_4 \rightarrow Li_2SO_4 + 2H_2O$

Breaking of lead bromide into lead and bromine is an example of _____.

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decomposition reaction
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synthesis reaction
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displacement reaction
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neutralisation reaction

Explanation

Decomposition reaction - separation of a substance into two or more substances that may differ from each other and from the original substance.

$PbBr_2 \rightarrow Pb+Br_2$

Find the values of w, x, y and z for the following reaction. Also, identify the type of reaction.

w(Potassium bromide) + x(Barium iodide)

$\longrightarrow$ y(Potassium iodide) + z(Barium bromide)

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1, 1, 1, 1 ; Double displacement reaction
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1, 1, 1, 1 ; Decomposition reaction
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2, 1, 2, 1 ; Double displacement reaction
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2, 1, 2, 1 ; Decomposition reaction

Explanation

Reaction:

$2KBr + BaI_2 \rightarrow 2KI + BaBr_2$

It is a double displacement reaction, also known as a double replacement reaction (is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products.)

In the reaction

$FeSO_4 + x\, \rightarrow\, Na_2SO_4 + Fe(OH)_2,x$ is:

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$Na_2SO_4$
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$H_2SO_4$
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$NaOH$
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None of these

Explanation

$FeSO_4 + 2NaOH \rightarrow Na_2SO_4 + Fe(OH)_2$

From the above reaction,

$x$ is

$NaOH$ .

So, correct option is

$C$ .

Which of the following is/are a decomposition reaction(s)?

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$\displaystyle 2HgO\quad \xrightarrow { Heat } \quad 2Hg+{ O }_{ 2 }$
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$\displaystyle { CaCO }_{ 3 }\quad \xrightarrow { Heat } \quad CaO+{ CO }_{ 2 }$
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$\displaystyle 2{ H }_{ 2 }O\quad \xrightarrow { Heat } \quad 2H_{ 2 }+{ O }_{ 2 }$
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All of these

Which of the following is a decomposition reaction ?

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$NaOH + HCl \rightarrow NaCl + H_2O$
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$NH_{4}CNO \rightarrow\ H_{2}NCONH_2$
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$2KClO_3 \rightarrow\ 2KCl + 3O_{2}$
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$H_{2} + I_{2} \rightarrow\ 2HI$

Explanation

Hint: A decomposition reaction can be defined as a chemical reaction in which one reactant breaks down into two or more products.

Correct Answer: Option

$C$

The explanation for the correct option:

A decomposition reaction occurs when one reactant breaks down into two or more products. This can be represented by the general equation:

$AB → A + B$

$2KClO_3 \rightarrow\ 2KCl + 3O_{2}$

Here, we can see reactant is broken into two products. So it is a decomposition reaction.

The explanation for incorrect options:

A).

The neutralization reaction can be defined as a chemical reaction in which an acid and base quantitatively react together to form salt and water as products.

acid + base(alkali) → salt + water

$NaOH + HCl \rightarrow NaCl + H_2O$

So option

$A$ is a neutralization reaction

B).

$NH_{4}CNO \rightarrow\ H_{2}NCONH_2$

It is not a decomposition reaction as we are getting a single product.

D).

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

$H_{2} + I_{2} \rightarrow\ 2HI$

Which of the following is the correctly balanced chemical equation?

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$Ca(OH)_2$ + $HF$ $\longrightarrow$ $2H_2O$ + $CaF_2$
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$Ca(OH)_2$ + $HF$ $\longrightarrow$ $2H_2O$ + $2CaF_2$
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$Ca(OH)_2$ + $2HF$ $\longrightarrow$ $2H_2O$ + $2CaF_2$
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$Ca(OH)_2$ + $2HF$ $\longrightarrow$ $2H_2O$ + $CaF_2$

Explanation

In the balanced equation, number of each atoms on reactant and product side are equal.

$Ca(OH)_2$ +

$2HF$

$\longrightarrow$

$2H_2O$ +

$CaF_2$

$\text {Atoms On reactant side (LHS) On product side (RHS)}$

$\text{ Ca 1 1 }$

$\text { O 2 2}$

$\text { H 4 4}$

$\text { F 2 2}$

Here, all the atoms on reactant and product side are same, hence, option

$D$ is correct.

The main cause of rancidity in foods is:

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bacteria
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proteins
0%
antioxidants
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oxidation of the fatty acid molecule

$CuO(s) + H_2(g) \rightarrow Cu(s) + H_2O(l)$

In this reaction, _______ is reduced.

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copper oxide
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copper
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hydrogen
0%
water

Explanation

$CuO(s) + H_2(g) \rightarrow Cu(s) + H_2O(l)$
In this reaction hydrogen gains oxygen and forms water, hence it is oxidised. On the other hand copper oxide loses oxygen and hence reduced.

Which of the following is not a decomposition reaction ?

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CaCO $_3$ $\rightarrow$ CaO + CO $_2$
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2KClO $_3$ $\rightarrow$ 2KCl + 3O $_2$
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Digestion of food in the body
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NaOH + HCl $\rightarrow$ NaCl + H $_2$ O

Explanation

Hint:

A decomposition reaction can be defined as a chemical reaction in which one reactant breaks down into two or more products.

Correct answer: $D$

Explanation for correct option :

(D)

$NaOH + HCl \rightarrow NaCl + H_2O$

A neutralization reaction can be defined as a chemical reaction in which an acid and base quantitatively react together to form salt and water as products.

acid + base(alkali) → salt + water

So option D is neutralization reaction

Explanation for incorrect options:

(A)

$CaCO_3 \rightarrow CaO + CO_2$

A decomposition reaction occurs when one reactant breaks down into two or more products. This can be represented by the general equation:

$AB → A + B$

$CaCO_3 \rightarrow CaO + CO_2$

Here, we can see reactant is broken into two products so we can say it is a decomposition reaction.

(B)

$2KClO_3 \rightarrow\ 2KCl + 3O_{2}$

A decomposition reaction occurs when one reactant breaks down into two or more products. This can be represented by the general equation:

$AB → A + B$

$2KClO_3 \rightarrow\ 2KCl + 3O_{2}$

Here, we can see reactant is broken into two products so we can say it is a decomposition reaction.

A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. Digestion in our body is also an example of decomposition reactions.

Write the balanced chemical reaction of the following:

If a copper coil is placed into a solution of silver nitrate, silver crystals form on the surface of the copper. Additionally, highly soluble copper (I) nitrate is generated.

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Cu(s) + 2AgNO $_3$ (aq) $\rightarrow$ Ag(s) + CuNO $_3$ (aq)
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2Cu(s) + AgNO $_3$ (aq) $\rightarrow$ Ag(s) + 2CuNO $_3$ (aq)
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Cu(s) + AgNO $_3$ (aq) $\rightarrow$ Ag(s) + 2CuNO $_3$ (aq)
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Cu(s) + AgNO $_3$ (aq) $\rightarrow$ Ag(s) + CuNO $_3$ (aq)

Explanation

$\textbf{Correct option: D}$

$\textbf{Explanation for correct option:}$

$\bullet$ The number of atoms of a particular element on the left-hand side should be equal to the number of atoms of a particular element on the right-hand side in a balanced chemical reaction.

$\bullet$ In given reaction a copper coil is placed in to a solution of silver nitrate, silver crystals form on the surface of the copper. Additionally, highly soluble copper(I) nitrate is generated .

$\bullet$ Chemical Equation for above reaction is :

$Cu(s) + AgNO_3(aq) \rightarrow Ag(s) + CuNO_3(aq)$

$\bullet$ Now balancing the given equation :

$\text{ Element Number of atoms on left side number of atoms on right side}$

$\text{ Cu 1 1}$

$\text{ Ag 1 1}$

$\text{ N 1 1}$

$\text{ O 3 3}$

$\bullet$ As all the number of atoms on the left-hand side and right-hand side of the reaction are the same hence it is a balanced chemical reaction.

$\textbf{Conclusion}:$ The balanced chemical reaction is,

$Cu(s) + AgNO_3(aq) \rightarrow Ag(s) + CuNO_3(aq)$

$\text{Additional information:}$

$\bullet$ When more reactive metals in reactivity series displaces less reactive metals from their salt solution is known as single displacement reaction.

Formation of nitric oxide from nitrogen and oxygen is a ______ reaction.

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combination
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displacement
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calcination
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roasting

Explanation

A combination reaction is a reaction where two or more elements or compounds (reactants) combine together to form a single compound (product).

$N_2+O_2 \rightarrow 2NO$

$Zn + xHCl \rightarrow ZnCl_2 + A$
In above equation A and x are :

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$H_2, 2$
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$Cl_2, 1$
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$H_2, 3$
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$H_2, 4$

Explanation

$Zn + 2HCl \rightarrow ZnCl_2 + H_2$

So, A=2 and x=2.

$\displaystyle xFe+yH_{2}O\rightarrow zFe_{3}O_{4}+wH_{2}$
What are

$x, y, z$ and

$w$ respectively ?

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1, 2, 3, 4
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2, 3, 1, 2
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3, 4, 1, 4
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3, 3, 3, 3

Explanation

Step-1 Write the unbalanced reaction.

$Fe + H_2O \rightarrow Fe_3O_4 + H_2$

Step-2 Compare the number of atoms of reactants with the number of atoms of products.

Element Reactants(no. of atoms) Products(no. of atoms)

$Fe$ 1 3

$H$ 2 2

$O$ 1 4

Step-3 Write the balanced reaction by equating both sides with the same number of all atoms.

$\displaystyle 3Fe+4H_{2}O\rightarrow 1Fe_{3}O_{4}+4H_{2}$

So,

$x = 3$

$y = 4$

$z = 1$

$w = 4$

Option C is correct.

Which of the following statement about the following reaction is correct

$ZnO + CO\, \rightarrow\, Zn +CO_2$

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$ZnO$ is being oxidised
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$CO$ is being reduced
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$CO_2$ is being oxidised
0%
$ZnO$ is being reduced

Explanation

In the reaction As

$ZnO$ has lost its oxygen to form

$Zn$ , therefore, we can say that it s being reduced.

The substances you start with are called ______ and after the chemical change, what is formed is called the _______.

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reactants, products
0%
reactants , gases
0%
element , products
0%
element , compounds

Explanation

A reactant is a substance that is present at the start of the chemical reaction or substances present to the left of the arrow in a chemical equation. A product is a substance that is present at the end of a chemical reaction or substance to the right of the arrow is called products.

For example,

$Zn + S \rightarrow ZnS$

In the above equation, zinc and sulfur are reactants that combine chemically to form the product zinc sulfide.

Select the correct alternative.

The reaction between acid and base to form salt and water is an example of :

0%
decomposition reaction
0%
combination reaction
0%
double displacement reaction
0%
neutralization reaction

Explanation

The reaction between acid and base produces salt and water, which is the example of neutralization reaction. This reaction follow mechanism of double displacement by displacing cation and anion from two different compounds.

$HCl + NaOH \rightarrow NaCl + H_2O$

Which of the following reaction will not take place?

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$Zn+FesO_4\rightarrow ZnSO_4+Fe$
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$2KI+Cl_2\rightarrow 2KCl+I_2$
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$Zn+MgSO_4\rightarrow ZnSO_4+Mg$
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$Mg+CuSO_4\rightarrow MgSO_4+Cu$

The term used to indicate the development of unpleasant smell and taste in fat and oil-containing foods due to aerial oxidation is:

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acidity
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radioactivity
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rabidity
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rancidity

The equation

$Cu+XHNO_3\rightarrow Cu(NO_3)_2+YNO_2+2H_2O$ , the values of

$X$ and

$Y$ are:

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3 and 1
0%
8 and 6
0%
1 and 1
0%
7 and 1

Explanation

The balanced chemical reaction is given beow:

$Cu+{ HNO }_{ 3 }\xrightarrow { } Cu\left[ { NO }_{ 3 } \right] _{ 2 }+{ NO }_{ 2 }+{ H }_{ 2 }O$

Hence, option

$C$ is correct.

Which of the following statement(s) about a balanced chemical equation is/are true?

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Mass is conserved
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Atoms are conserved
0%
Both A and B
0%
None of these

Explanation

$\textbf{Correct option: (C)}$

$\textbf{Explanation of correct option:}$

$\bullet$ A balanced chemical equation is defined as an equation, having same number of atoms of each element equal on both reactant and product side.

$\bullet$ To obey this law, the total mass of element present in reactant side must be equal total mass present in product side

$\bullet$ Hence, option C is correct.

Determine the reaction type for the given reaction.

$P_4O_{10}+6H_2O\rightarrow 4H_3PO_4$

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

Copper sulphate solution, which is blue in colour, will change to a colourless solution with the addition of which metal?

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$Au$
0%
$Ag$
0%
$Zn$
0%
All of these

Explanation

As we know, among given metals only

$Zn$ is more reactive than

$Cu$ so it will replace

$Cu$ and forms a colourless solution.

$Zn+CuSO_4 \rightarrow ZnSO_4 + Cu$

When the following equation is balanced, the coefficients

$a, b$ and

$c$ will be:

$aKClO_3 \rightarrow bKCl + cO_2$

0%
1, 2, 2
0%
2, 1, 3
0%
1, 3, 3
0%
2, 2, 3

Explanation

An equation is balanced when the same number of atoms of each element are present on either side of the reaction.

When the coefficients are

$a = \ 2, b= \ 2 \ and \ c= \ 3$ , the reaction is balanced, with equal number of each atom on either side.

$2KClO_3 \rightarrow 2KCl + 3O_2$

The reaction

$\mathrm{2Na}+\mathrm{Cl}_2\rightarrow \mathrm{2NaCl}$ is an example of:

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

Explanation

$\mathrm{2Na}+\mathrm{Cl}_2\rightarrow \mathrm{2NaCl}$

In the reaction, two different elements are combining together to form a compound. Therefore, it is a combination reaction. Combination reaction is a reaction in which two or more simple substances combine under suitable conditions to form a single compound.

Consider the following statements about a chemical reaction. Which one is true?

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The total number of molecules remains unchanged
0%
The total number of moles remains the same
0%
The total mass is not altered
0%
The total number of reaction molecules is equal to the total number of molecules of the products formed

Explanation

A number of molecules or moles may get change in a chemical reaction. Also, the number of reactant molecules need not be equal to product molecules. They may get less if association reaction takes place or they may get increase due to dissociation reaction.

But, according to the law of mass conservation, for any chemical reaction, the total mass remains constant at all times.

Hence, Option

$C$ is correct.

Which of the statement is correct about the following reaction?

$2KClO_3(s)\underset {catalyst}{\xrightarrow {Heat}}2KCl(s)+3O_2(g)$

0%
It is a decomposition reaction and endothermic in nature.
0%
It is a combination reaction.
0%
It is a decomposition reaction and is accompanied by the evolution of heat.
0%
It is a photochemical decomposition reaction and exothermic in nature.

Consider the following reactions :

$CuSO_4+Fe\rightarrow FeSO_4+Cu$

$FeSO_4+Zn\rightarrow ZnSO_4+Fe$
Among these:

0%
$Zn$ is most reactive and $Fe$ is least reactive
0%
$Fe$ is most reactive and $Cu$ is least reactive
0%
$Zn$ is most reactive and $Cu$ is least reactive
0%
$Cu$ is most reactive and $Fe$ is least reactive

Explanation

Metals which can displace other metals from their solution are comparatively more reactive than the metal present in solution. Thus,

$Fe$ is more reactive than

$Cu$ and

$Zn$ is more reactive than

$Fe$ .

Which of the following processes can not take place in the absence of oxygen?

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Combustion
0%
Displacement
0%
Combination
0%
All of the above

CBSE Questions for Class 10 Chemistry Chemical Reactions And Equations Quiz 4 - 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 4 - MCQExams.com

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Practice Class 10 Chemistry Quiz Questions and Answers

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