Redox Reactions — DPP 2

20 NEET questions from Redox Reactions, with answers and explanations. Attempt it as a timed test to get scoring, accuracy breakdown and mistake tracking.

Attempt this test free 20 questions · 30 minutes · +80 marks
1
In the reaction: $\mathrm { Zn } + \mathrm { Cu } ^ { 2 + } \rightarrow \mathrm { Zn } ^ { 2 + } + \mathrm { Cu }$, which of the following statements is true?
  1. A Zn is oxidised and $\mathrm { Cu } ^ { 2 + }$ is reduced.
  2. B Zn is reduced and $\mathrm { Cu } ^ { 2 + }$ is oxidised.
  3. C Both Zn and $\mathrm { Cu } ^ { 2 + }$ are oxidised.
  4. D Both Zn and $\mathrm { Cu } ^ { 2 + }$ are reduced.
Show answer

Correct answer: A

2
Oxidation numbers of $\mathrm{P}^{\circ} \mathrm{PO}_{4}^{2-}, \mathrm{S}$ in $\mathrm{SO}_{4}^{2-}$ and $\mathrm{Cr}^{2-}$ in $\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}$ are respectively;.
  1. A +5, +6 and +6
  2. B +3, +6 and +5
  3. C +5, +3 and +6
  4. D –3, +6 and +6
Show answer & explanation

Correct answer: A

(I) $\mathrm{XO}_{4}^{3-} \Rightarrow x+4 \times(-2)$ =-3
x = -3 + 8 = +5
Oxidation number of $\mathrm{P}=+5$.

(II) $\mathrm{SO}_{4}^{2-} \Rightarrow x+4 \times(-2)$ = -2
x = -2 + 8 $\Rightarrow$ x = +6
Oxidation number of $\mathrm{S}=+6$.

(III)
$\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-} \Rightarrow 2 \mathrm{x}+7 \times(-2)$ = -2
2$\mathrm{x}$ = -2 + 14
$\Rightarrow 2 \mathrm{x}$ = 12
$\mathrm{x}$ = $\frac{12}{2}$ = +6
Oxidation number of Cr = +6.
Therefore, option (1) is the correct answer
3
The oxidation number and covalency of sulphur in sulphur molecules $\left( \mathrm { S } _ { 8 } \right)$ are;
  1. A 0 and 2
  2. B + 6 and 8
  3. C 0 and 8
  4. D + 6 and 2
Show answer

Correct answer: A

4
Directions: These questions consist of two statements each, printed as Assertion (A) and Reason (R). While answering these questions, you are required to choose any one of the following four responses.
Assertion (A): Bromide ion acts as a reducing agent in the given reaction.
2MnO$^{–}$$_{4}$ (aq) + Br$^{–}$(aq) + H₂O(l) → 2MnO$_{2}$(aq) + 3BrO$^{–}$$_{3}$ (aq) + 2OH$^{–}$(aq)
Reason (R): Because in this reaction bromide ion is reducing MnO–4 ion as oxidation number of bromine increases from –1 to 5.
  1. A If both Assertion (A) and Reason (R) are True and the Reason (R) is a correct explanation of the Assertion (A).
  2. B If both Assertion (A) and Reason (R) are True but Reason (R) is not a correct explanation of the Assertion (A).
  3. C If Assertion (A) is True but the Reason (R) is False.
  4. D Assertion (A) is False but Reason (R) is True.
Show answer

Correct answer: A

5
Which of the following statements is correct?
  1. A Oxidizing agents undergoes oxidation.
  2. B Reducing agents undergoes reduction.
  3. C Oxidizing agents gain electrons.
  4. D Reducing agents gain electrons.
Show answer

Correct answer: C

6
Directions: These questions consist of two statements each, printed as Assertion (A) and Reason (R). While answering these questions, you are required to choose any one of the following four responses.
Assertion (A): The decomposition of hydrogen peroxide to form water and oxygen is an example of disproportionation reaction.
Reason (R): The oxygen of peroxide is in –1 oxidation state and it is converted to zero oxidation state in O₂ and –2 oxidation state in H₂O.
  1. A If both Assertion (A) and Reason (R) are True and the Reason (R) is a correct explanation of the Assertion (A).
  2. B If both Assertion (A) and Reason (R) are True but Reason (R) is not a correct explanation of the Assertion (A)
  3. C If Assertion (A) is True but the Reason (R) is False
  4. D Assertion (A) is False but Reason (R) is True
Show answer

Correct answer: A

7
Which of the following reactions is an example of a displacement redox reaction?
  1. A $2 \mathrm { Fe } + 3 \mathrm { Cl } _ { 2 } \rightarrow 2 \mathrm { FeCl } _ { 3 }$
  2. B $\mathrm { Cu } + 2 \mathrm { AgNO } _ { 3 } \rightarrow 2 \mathrm { Ag } + \mathrm { Cu } \left( \mathrm { NO } _ { 3 } \right) _ { 2 }$
  3. C $2 \mathrm { H } _ { 2 } + \mathrm { O } _ { 2 } \rightarrow 2 \mathrm { H } _ { 2 } \mathrm { O }$
  4. D $2 \mathrm { KClO } _ { 3 } \rightarrow 2 \mathrm { KCl } + 3 \mathrm { O } _ { 2 }$
Show answer

Correct answer: B

8
According to classical concept, oxidation involves;
  1. A addition of oxygen.
  2. B addition of electronegative element.
  3. C removal of either hydrogen or some electropositive element.
  4. D All of these
Show answer

Correct answer: D

9
Which of the following is a combination redox reaction?
  1. A $2 \mathrm { Na } + 2 \mathrm { H } _ { 2 } \mathrm { O } \rightarrow 2 \mathrm { NaOH } + \mathrm { H } _ { 2 }$
  2. B $2 \mathrm { Mg } + \mathrm { O } _ { 2 } \rightarrow 2 \mathrm { MgO }$
  3. C $2 \mathrm { KClO } _ { 3 } \rightarrow 2 \mathrm { KCl } + 3 \mathrm { O } _ { 2 }$
  4. D $\mathrm { Zn } + \mathrm { CuSO } _ { 4 } \rightarrow \mathrm { ZnSO } _ { 4 } + \mathrm { Cu }$
Show answer

Correct answer: B

10
The species among the following that does not show a disproportionation reaction is; $\mathrm { ClO } ^ { - } , \mathrm { ClO } _ { 2 } ^ { - } , \mathrm { ClO } _ { 3 } ^ { - }$and $\mathrm { ClO } _ { 4 } ^ { - }$
  1. A $\mathrm { ClO } ^ { - }$
  2. B $\mathrm { ClO } _ { 2 } ^ { - }$
  3. C $\mathrm { ClO } _ { 4 } ^ { - }$
  4. D $\mathrm { ClO } _ { 3 } ^ { - }$
Show answer

Correct answer: C

11
The oxidation number of ' Mg ' in $\mathrm { Mg } \left( \mathrm { H } _ { 2 } \mathrm { PO } _ { 2 } \right) _ { 2 }$ is;
  1. A + 3
  2. B + 2
  3. C + 1
  4. D - 1
Show answer

Correct answer: B

12
Which of the following is not a disproportionation reaction?
  1. A $2 \mathrm { H } _ { 2 } \mathrm { O } _ { 2 } \rightarrow 2 \mathrm { H } _ { 2 } \mathrm { O } + \mathrm { O } _ { 2 }$
  2. B $2 \mathrm { Cu } ^ { + } \rightarrow \mathrm { Cu } + \mathrm { Cu } ^ { 2 + }$
  3. C $\mathrm { MnO } _ { 4 } ^ { - } + 4 \mathrm { H } ^ { + } + 3 \mathrm { e } ^ { - } \rightarrow \mathrm { MnO } _ { 2 } + 2 \mathrm { H } _ { 2 } \mathrm { O }$
  4. D $2 \mathrm { NO } _ { 2 } + \mathrm { H } _ { 2 } \mathrm { O } \rightarrow \mathrm { HNO } _ { 3 } + \mathrm { HNO } _ { 2 }$
Show answer

Correct answer: C

13
In a reaction, $\mathrm { H } _ { 2 } \mathrm { O } + \mathrm { C } \rightarrow \mathrm { CO } + \mathrm { H } _ { 2 }$ :
  1. A $\mathrm { H } _ { 2 } \mathrm { O }$ is the reducing agent.
  2. B $\mathrm { H } _ { 2 } \mathrm { O }$ is the oxidising agent.
  3. C carbon is the oxidising agent.
  4. D oxidation reduction does not occur.
Show answer

Correct answer: B

14
Which of the following examples does not represent disproportionation?
  1. A $3 \mathrm{H}_{3} \mathrm{PO}_{2} \rightarrow \mathrm{PH}_{3}+2 \mathrm{H}_{3} \mathrm{PO}_{3}$
  2. B $2 \mathrm{H}_{2} \mathrm{O}_{2} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}$
  3. C $3 \mathrm{KClO}_{4}+\mathrm{KCl} \rightarrow 4 \mathrm{KClO}_{3}$
  4. D $3 \mathrm{Cl}_{2}+6 \mathrm{NaOH} \rightarrow 5 \mathrm{NaCl}+\mathrm{NaClO}_{3}+3 \mathrm{H}_{2} \mathrm{O}$
Show answer

Correct answer: C

15
Which one of the following is not a redox reaction?
  1. A $\mathrm { CaCO } _ { 3 } \rightarrow \mathrm { CaO } + \mathrm { CO } _ { 2 }$
  2. B $2 \mathrm { H } _ { 2 } + \mathrm { O } _ { 2 } \rightarrow 2 \mathrm { H } _ { 2 } \mathrm { O }$
  3. C $\mathrm { Na } + \mathrm { H } _ { 2 } \mathrm { O } \rightarrow \mathrm { NaOH } + \frac { 1 } { 2 } \mathrm { H } _ { 2 }$
  4. D $\mathrm{MnCl}_{3} \rightarrow \mathrm{MnCl}_{2}+\frac{1}{2} \mathrm{Cl}_{2}$
Show answer

Correct answer: A

16
In which of the following reactions does a metal displace another element from its compound?
  1. A $2 \mathrm { H } _ { 2 } + \mathrm { O } _ { 2 } \rightarrow 2 \mathrm { H } _ { 2 } \mathrm { O }$
  2. B $2 \mathrm { KClO } _ { 3 } \rightarrow 2 \mathrm { KCl } + 3 \mathrm { O } _ { 2 }$
  3. C $\mathrm { Zn } + \mathrm { CuSO } _ { 4 } \rightarrow \mathrm { ZnSO } _ { 4 } + \mathrm { Cu }$
  4. D $\mathrm { N } _ { 2 } + 3 \mathrm { H } _ { 2 } \rightarrow 2 \mathrm { NH } _ { 3 }$
Show answer

Correct answer: C

17
The oxidation number of oxygen in $\mathrm { O } _ { 3 }$ is:
  1. A + 1
  2. B + 1
  3. C 0
  4. D - 3
Show answer

Correct answer: C

18
Which of the following is the most powerful oxidising agent?
  1. A $\mathrm { F } _ { 2 }$
  2. B $\mathrm { O } _ { 2 }$
  3. C $\mathrm { Br } _ { 2 }$
  4. D $\mathrm { I } _ { 2 }$
Show answer

Correct answer: A

19
Oxidation number of N in $\mathrm { HNO } _ { 3 }$ is;
  1. A - 3.5
  2. B + 3.5
  3. C $- 3 , + 5$
  4. D + 5
Show answer

Correct answer: D

20
Which of the following is a reducing agent in the reaction:
$\mathrm { C } + \mathrm { O } _ { 2 } \rightarrow \mathrm { CO } _ { 2 }$
  1. A C
  2. B $\mathrm { O } _ { 2 }$
  3. C $\mathrm { CO } _ { 2 }$
  4. D None of the above
Show answer

Correct answer: A

Attempt this as a timed test

Reading answers is not the same as sitting the paper. Attempt it timed and you get your score, per-question timing, and the mistakes tracked for revision.

Start free

More Redox Reactions tests

Redox Reactions — DPP 1 20 Q Redox Reactions — DPP 3 20 Q
All Redox Reactions tests →