Chemical Reactions and Equations Test

Result

Chemical Reactions and Equations Test - 30

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

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

A
$$Au$$

B
$$Ag$$

C
$$Zn$$

D
All of these

Solution

As we know, among given metals only $$Zn$$ is more reactive than $$Cu$$ so it will replace $$Cu$$ and forms a colourless solution.
$$Zn+CuSO_4 \rightarrow ZnSO_4 + Cu$$
Question 2
1 / -0

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

A
$$\displaystyle 2HgO\quad \xrightarrow { Heat } \quad 2Hg+{ O }_{ 2 }$$

B
$$\displaystyle { CaCO }_{ 3 }\quad \xrightarrow { Heat } \quad CaO+{ CO }_{ 2 }$$

C
$$\displaystyle 2{ H }_{ 2 }O\quad \xrightarrow { Heat } \quad 2H_{ 2 }+{ O }_{ 2 }$$

D
All of these

Solution
Question 3
1 / -0

$$\displaystyle xFe+yH_{2}O\rightarrow zFe_{3}O_{4}+wH_{2}$$
What are $$x, y, z$$ and $$w$$ respectively ?

A
1, 2, 3, 4

B
2, 3, 1, 2

C
3, 4, 1, 4

D
3, 3, 3, 3

Solution

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.
Question 4
1 / -0

Which of the following statement about the following reaction is correct
$$ZnO + CO\, \rightarrow\, Zn +CO_2$$

A
$$ZnO$$ is being oxidised

B
$$CO$$ is being reduced

C
$$CO_2$$ is being oxidised

D
$$ZnO$$ is being reduced

Solution

In the reaction As $$ZnO$$ has lost its oxygen to form $$Zn$$, therefore, we can say that it s being reduced.
Question 5
1 / -0

When the following equation is balanced, the coefficients $$a, b$$ and $$c$$ will be:
$$aKClO_3 \rightarrow bKCl + cO_2$$

A
1, 2, 2

B
2, 1, 3

C
1, 3, 3

D
2, 2, 3

Solution

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.
$$ 2KClO_3 \rightarrow 2KCl + 3O_2$$
Question 6
1 / -0

Which of the following reaction will not take place?

A
$$Zn+FesO_4\rightarrow ZnSO_4+Fe$$

B
$$2KI+Cl_2\rightarrow 2KCl+I_2$$

C
$$Zn+MgSO_4\rightarrow ZnSO_4+Mg$$

D
$$Mg+CuSO_4\rightarrow MgSO_4+Cu$$

Solution

The reactivity series is a list of metals arranged in the order of their decreasing activities. Zn comes after Mg in the reactivity series. Hence, zinc cannot displace magnesium from magnesium sulfate and reaction is not possible.
Question 7
1 / -0

Consider the following reactions :
$$CuSO_4+Fe\rightarrow FeSO_4+Cu$$
$$FeSO_4+Zn\rightarrow ZnSO_4+Fe$$
Among these:

A
$$Zn$$ is most reactive and $$Fe$$ is least reactive

B
$$Fe$$ is most reactive and $$Cu$$ is least reactive

C
$$Zn$$ is most reactive and $$Cu$$ is least reactive

D
$$Cu$$ is most reactive and $$Fe$$ is least reactive

Solution

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 $$Fe$$.
Question 8
1 / -0

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

A
Combustion

B
Displacement

C
Combination

D
All of the above

Solution

Combustion requires oxygen as a prime reagent.
In displacement reaction, one element displaces a less reactive element from the compound. It does not require oxygen for the reaction to take place.
In combination reaction, two or more reactants combine to form a single product. It too can take place without oxygen.
So, the correct option is A.
Question 9
1 / -0

Action of light on silver bromide is an example of?

A
Exothermic reaction

B
Endothermic reaction

C
Chemical combination

D
Displacement reaction

Solution

Endothermic reactions are those in which energy is absorbed. In the reaction of silver bromide, sunlight is absorbed and so, silver bromide decomposes into silver and bromine. This is a decomposition reaction, not a combination or displacement reaction.

$$2AgBr \xrightarrow{sunlight} 2Ag + Br_2$$
Question 10
1 / -0

The equation $$Cu+XHNO_3\rightarrow Cu(NO_3)_2+YNO_2+2H_2O$$, the values of $$X$$ and $$Y$$ are:

A
3 and 1

B
8 and 6

C
1 and 1

D
7 and 1

Solution

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.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Chemical Reactions and Equations Test - 30

Result

Chemical Reactions and Equations Test - 30

Score

-

Rank

-

SHARING IS CARING

Question 1

$$Au$$

$$Ag$$

$$Zn$$

All of these

Solution

Question 2

$$\displaystyle 2HgO\quad \xrightarrow { Heat } \quad 2Hg+{ O }_{ 2 }$$

$$\displaystyle { CaCO }_{ 3 }\quad \xrightarrow { Heat } \quad CaO+{ CO }_{ 2 }$$

$$\displaystyle 2{ H }_{ 2 }O\quad \xrightarrow { Heat } \quad 2H_{ 2 }+{ O }_{ 2 }$$

All of these

Solution

Question 3

1, 2, 3, 4

2, 3, 1, 2

3, 4, 1, 4

3, 3, 3, 3

Solution

Question 4

$$ZnO$$ is being oxidised

$$CO$$ is being reduced

$$CO_2$$ is being oxidised

$$ZnO$$ is being reduced

Solution

Question 5

1, 2, 2

2, 1, 3

1, 3, 3

2, 2, 3

Solution

Question 6

$$Zn+FesO_4\rightarrow ZnSO_4+Fe$$

$$2KI+Cl_2\rightarrow 2KCl+I_2$$

$$Zn+MgSO_4\rightarrow ZnSO_4+Mg$$

$$Mg+CuSO_4\rightarrow MgSO_4+Cu$$

Solution

Question 7

$$Zn$$ is most reactive and $$Fe$$ is least reactive

$$Fe$$ is most reactive and $$Cu$$ is least reactive

$$Zn$$ is most reactive and $$Cu$$ is least reactive

$$Cu$$ is most reactive and $$Fe$$ is least reactive

Solution

Question 8

Combustion

Displacement

Combination

All of the above

Solution

Question 9

Exothermic reaction

Endothermic reaction

Chemical combination

Displacement reaction

Solution

Question 10

3 and 1

8 and 6

1 and 1

7 and 1

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.