Redox Reactions — DPP 3

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
What is the oxidation state of P in $\mathrm { Ba } \left( \mathrm { H } _ { 2 } \mathrm { PO } _ { 2 } \right) _ { 2 }$ ?
  1. A + 1
  2. B + 2
  3. C + 3
  4. D - 1
Show answer

Correct answer: A

2
The oxidation number of chlorine in HOCl is;
  1. A - 1
  2. B 0
  3. C + 1
  4. D 2
Show answer

Correct answer: C

3
$3 \mathrm { Fe } + 4 \mathrm { H } _ { 2 } \mathrm { O } \rightarrow \mathrm { Fe } _ { 3 } \mathrm { O } _ { 4 } + 4 \mathrm { H } _ { 2 }$ is a $\_\_\_\_$ redox reaction.
  1. A decomposition
  2. B single displacement
  3. C combination
  4. D double displacement
Show answer

Correct answer: B

4
Oxidation number of ' N ' in $\mathrm { N } _ { 3 } \mathrm { H }$ (hydrazoic acid) is:
  1. A $- 1 / 3$
  2. B + 3
  3. C 0
  4. D - 3
Show answer

Correct answer: A

5
In which of the following reactions, the underlined substance has been oxidised?
  1. A $\mathrm { Br } _ { 2 } + \mathrm { H } _ { 2 } \mathrm {~S} \rightarrow 2 \mathrm { HBr } + \mathrm { S }$
  2. B $2 \mathrm { HgCl } _ { 2 } + \mathrm { SnCl } _ { 2 } \rightarrow \mathrm { Hg } _ { 2 } \mathrm { Cl } _ { 2 } + \mathrm { SnCl } _ { 4 }$
  3. C $\mathrm { Cl } _ { 2 } + 2 \mathrm { KI } \rightarrow 2 \mathrm { KCl } + \mathrm { I } _ { 2 }$
  4. D $2 \underline { \mathrm { Cu } } ^ { 2 + } + 4 \mathrm { I } ^ { - } \rightarrow \mathrm { Cu } _ { 2 } \mathrm { I } _ { 2 } + \mathrm { I } _ { 2 }$
Show answer

Correct answer: C

6
In the conversion of $\mathrm { Br } _ { 2 }$ to $\mathrm { BrO } _ { 3 } ^ { - }$, the oxidation number of Br changes from;
  1. A 0 to + 5
  2. B + 1 to + 5
  3. C 0 to - 3
  4. D + 2 to + 5
Show answer

Correct answer: A

7
Which of the following reactions is a redox reaction?
  1. A $\mathrm { H } _ { 2 } + \mathrm { Cl } _ { 2 } \rightarrow 2 \mathrm { HCl }$
  2. B $\mathrm { NaOH } + \mathrm { HCl } \rightarrow \mathrm { NaCl } + \mathrm { H } _ { 2 } \mathrm { O }$
  3. C $\mathrm { BaCl } _ { 2 } + \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } \rightarrow \mathrm { BaSO } _ { 4 } + 2 \mathrm { HCl }$
  4. D $\mathrm { CaCO } _ { 3 } \rightarrow \mathrm { CaO } + \mathrm { CO } _ { 2 }$
Show answer

Correct answer: A

8
In the reaction:
$2 \mathrm { MnO } _ { 4 } ^ { - } + 16 \mathrm { H } ^ { + } + 5 \mathrm { C } _ { 2 } \mathrm { O } _ { 4 } ^ { 2 - } \rightarrow 2 \mathrm { Mn } ^ { 2 + } + 8 \mathrm { H } _ { 2 } \mathrm { O } + 10 \mathrm { CO } _ { 2 }$,
the oxidation number of Mn in $\mathrm { MnO } _ { 4 } ^ { - }$changes from;
  1. A + 7 to + 2
  2. B + 5 to + 3
  3. C + 4 to + 1
  4. D + 6 to + 2
Show answer

Correct answer: A

9
In $\mathrm { Cu } ^ { 2 + } + \mathrm { Ag } \rightarrow \mathrm { Cu } + \mathrm { Ag } ^ { + }$, oxidation half-reaction is:
  1. A $\mathrm { Cu } ^ { 2 + } + 2 \mathrm { e } ^ { - } \rightarrow \mathrm { Cu }$
  2. B $\mathrm { Ag } \rightarrow \mathrm { Ag } ^ { + } + \mathrm { e } ^ { - }$
  3. C $\mathrm { Cu } \rightarrow \mathrm { Cu } ^ { 2 + } + 2 \mathrm { e } ^ { - }$
  4. D $\mathrm { Ag } ^ { + } + \mathrm { e } ^ { - } \rightarrow \mathrm { Ag }$
Show answer

Correct answer: B

10
Which one can act as an oxidising and a reducing agent both?
  1. A $\mathrm { HNO } _ { 2 }$
  2. B $\mathrm { H } _ { 2 } \mathrm { O } _ { 2 }$
  3. C $\mathrm { H } _ { 2 } \mathrm { SO } _ { 3 }$
  4. D All of these
Show answer

Correct answer: D

11
Which of the following species has the highest oxidation state?
  1. A Mn in $\mathrm { MnO } _ { 2 }$
  2. B Cr in $\mathrm { CrO } _ { 4 } ^ { 2 - }$
  3. C Fe in $\mathrm { Fe } _ { 2 } \mathrm { O } _ { 3 }$
  4. D Cl in $\mathrm { HClO } _ { 4 }$
Show answer

Correct answer: D

12
In which of the following reactions, $\mathrm { H } _ { 2 } \mathrm { O } _ { 2 }$ acts as a reducing agent?
  1. A $\mathrm { HOCl } ( \mathrm { aq } ) + \mathrm { H } _ { 2 } \mathrm { O } _ { 2 } ( \mathrm { aq } ) \xrightarrow { \mathrm { H } ^ { + } } \mathrm { H } _ { 3 } \mathrm { O } ^ { + } ( \mathrm { aq } ) + \mathrm { Cl } ^ { - } ( \mathrm { aq } ) + \mathrm { O } _ { 2 } ( \mathrm {~g} )$
  2. B $\mathrm { Mn } ^ { 2 + } ( \mathrm { aq } ) + \mathrm { H } _ { 2 } \mathrm { O } _ { 2 } ( \mathrm { aq } ) \xrightarrow { \mathrm { OH } ^ { - } } \mathrm { Mn } ^ { 4 + } ( \mathrm { aq } ) + 2 \mathrm { OH } ^ { - } ( \mathrm { aq } )$
  3. C $2 \mathrm { Fe } ^ { 2 + } ( \mathrm { aq } ) + \mathrm { H } _ { 2 } \mathrm { O } _ { 2 } ( \mathrm { aq } ) \xrightarrow { \mathrm { OH } ^ { - } } 2 \mathrm { Fe } ^ { 3 + } ( \mathrm { aq } ) + 2 \mathrm { OH } ^ { - } ( \mathrm { aq } )$
  4. D $\mathrm { PbS } ( \mathrm { s } ) + 4 \mathrm { H } _ { 2 } \mathrm { O } _ { 2 } ( \mathrm { aq } ) \xrightarrow { \mathrm { H } ^ { * } } \mathrm { PbSO } _ { 4 } ( \mathrm {~s} ) + 4 \mathrm { H } _ { 2 } \mathrm { O } ( \mathrm { l } )$
Show answer

Correct answer: A

13
Which oxidation states of phosphorus cannot be found in the disproportionation reaction below? $\mathrm { P } _ { 2 } \mathrm { H } _ { 4 } \rightarrow \mathrm { PH } _ { 3 } + \mathrm { P } _ { 4 } \mathrm { H } _ { 2 }$
  1. A - 2
  2. B - 3
  3. C + 3
  4. D $- \frac { 1 } { 2 }$
Show answer

Correct answer: C

14
The oxidation number of P is + 3 in:
  1. A $\mathrm { H } _ { 3 } \mathrm { PO } _ { 3 }$
  2. B $\mathrm { H } _ { 3 } \mathrm { PO } _ { 4 }$
  3. C $\mathrm { HPO } _ { 3 }$
  4. D $\mathrm { H } _ { 4 } \mathrm { P } _ { 2 } \mathrm { O } _ { 7 }$
Show answer

Correct answer: A

15
In which of the following reactions, $\mathrm { HNO } _ { 3 }$ does not behave as an oxidising agent?
  1. A $\mathrm { I } _ { 2 } + 10 \mathrm { HNO } _ { 3 } \rightarrow 2 \mathrm { HIO } _ { 3 } + 10 \mathrm { NO } _ { 2 } + 4 \mathrm { H } _ { 2 } \mathrm { O }$
  2. B $3 \mathrm { Cu } + 8 \mathrm { HNO } _ { 3 } \rightarrow 3 \mathrm { Cu } \left( \mathrm { NO } _ { 3 } \right) _ { 2 } + 2 \mathrm { NO } + 4 \mathrm { H } _ { 2 } \mathrm { O }$
  3. C $4 \mathrm { Zn } + 10 \mathrm { HNO } _ { 3 } \rightarrow 4 \mathrm { Zn } \left( \mathrm { NO } _ { 3 } \right) _ { 2 } + \mathrm { NH } _ { 4 } \mathrm { NO } _ { 3 } + 3 \mathrm { H } _ { 2 } \mathrm { O }$
  4. D $2 \mathrm { HNO } _ { 3 } + \mathrm { P } _ { 2 } \mathrm { O } _ { 5 } \rightarrow 2 \mathrm { HPO } _ { 3 } + \mathrm { N } _ { 2 } \mathrm { O } _ { 5 }$
Show answer

Correct answer: D

16
In the reaction,
$3 \mathrm { Br } _ { 2 } + 6 \mathrm { CO } _ { 3 } ^ { 2 - } + 3 \mathrm { H } _ { 2 } \mathrm { O } \rightarrow 5 \mathrm { Br } ^ { - } + \mathrm { BrO } _ { 3 } ^ { - } + 6 \mathrm { HCO } _ { 3 } ^ { - }$
  1. A bromine is oxidised and carbonate is reduced.
  2. B bromine is oxidised as well as reduced.
  3. C bromine is reduced and water is oxidised.
  4. D $\mathrm { Br } _ { 2 }$ is neither oxidised nor reduced.
Show answer

Correct answer: B

17
Which compound cannot be used as an oxidising agent?
  1. A $\mathrm { NH } _ { 3 }$
  2. B $\mathrm { HNO } _ { 3 }$
  3. C $\mathrm { KMnO } _ { 4 }$
  4. D $\mathrm { O } _ { 3 }$
Show answer

Correct answer: A

18
Which of the following is a redox reaction?
  1. A $2 \mathrm { CuSO } _ { 4 } + 4 \mathrm { KI } \rightarrow \mathrm { Cu } _ { 2 } \mathrm { I } _ { 2 } + 2 \mathrm {~K} _ { 2 } \mathrm { SO } _ { 4 } + \mathrm { I } _ { 2 }$
  2. B $\mathrm { SO } _ { 2 } + \mathrm { H } _ { 2 } \mathrm { O } \rightarrow \mathrm { H } _ { 2 } \mathrm { SO } _ { 3 }$
  3. C $\mathrm { Na } _ { 2 } \mathrm { SO } _ { 4 } + \mathrm { BaCl } _ { 2 } \rightarrow \mathrm { BaSO } _ { 4 } + 2 \mathrm { NaCl }$
  4. D $\mathrm { CuSO } _ { 4 } + 4 \mathrm { NH } _ { 3 } \rightarrow \left[ \mathrm { Cu } \left( \mathrm { NH } _ { 3 } \right) _ { 4 } \right] \mathrm { SO } _ { 4 }$
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Correct answer: A

19
The oxidation number of the sulphur atoms in peroxomonosulphuric acid $\mathrm { H } _ { 2 } \mathrm { SO } _ { 5 }$ and peroxodisulphuric $\left( \mathrm { H } _ { 2 } \mathrm {S} _ { 2 } \mathrm { O } _ { 8 } \right)$ respectively are;
  1. A + 8 and + 7
  2. B + 3 and + 3
  3. C + 6 and + 6
  4. D + 4 and + 6
Show answer

Correct answer: C

20
Oxidation takes place with;
  1. A gain of electrons.
  2. B loss of electrons.
  3. C increase in the valency of negative part.
  4. D decrease in the valency of positive part.
Show answer

Correct answer: B

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