Quiz - chemistry - Redox Reaction-PYQ

Q1. Which of the following is a redox reaction? Source: orcusprep.in

NEET 1997

easy

Evaporation of \( H_{2}O \)

Both oxidation and reduction

\( H_{2}SO_{4} \) with \( NaOH \)

In atmosphere \( O_{3} \) from \( O_{2} \) by lightning

Q2. Without losing its concentration, \( ZnCl_{2} \) solution cannot be kept in contact with Source: orcusprep.in

NEET 1998

easy

Pb

Al

Au

Ag

Q3. What is the change in oxidation number of carbon in the following reaction?
\( CH_{4}(g) + 4Cl_{2}(g) \rightarrow CCl_{4}(l) + 4HCl(g) \) Source: orcusprep.in

NEET 2020

easy

+ 4 to + 4

0 to + 4

– 4 to + 4

0 to – 4

Q4. The correct structure of tribromooctaoxide is Source: orcusprep.in

NEET 2019

medium

A structure with a \( Br-Br-Br \) chain, where the central Br is bonded to two O atoms and each terminal Br is bonded to three O atoms.

A linear chain of three Br atoms each bonded to three O atoms.

A cyclic structure of Br atoms with O atoms attached to them.

A structure with a single Br atom bonded to eight O atoms.

Q5. Which of the following reactions are disproportionation reactions?
(i) \( 2Cu^{+} \rightarrow Cu^{2+} + Cu^{0} \)
(ii) \( 3MnO_{4}^{2-} + 4H^{+} \rightarrow 2MnO_{4}^{-} + MnO_{2} + 2H_{2}O \)
(iii) \( 2KMnO_{4} \rightarrow K_{2}MnO_{4} + MnO_{2} + O_{2} \)
(iv) \( 2MnO_{4}^{-} + 3Mn^{2+} + 2H_{2}O \rightarrow 5MnO_{2} + 4H^{+} \)
Select the correct option from the following. Source: orcusprep.in

NEET 2019

medium

(i) and (iv) only

(i) and (ii) only

(i), (ii) and (iii)

(i), (iii) and (iv)

Q6. The oxidation state of Cr in \( CrO_{5} \) is Source: orcusprep.in

NEET 2019, 2014

medium

–6

+12

+6

+4

Q7. The correct order of N-compounds in its decreasing order of oxidation states is Source: orcusprep.in

NEET 2018

easy

\( HNO_{3}, NO, N_{2}, NH_{4}Cl \)

\( HNO_{3}, NO, NH_{4}Cl, N_{2} \)

\( HNO_{3}, NH_{4}Cl, NO, N_{2} \)

\( NH_{4}Cl, N_{2}, NO, HNO_{3} \)

Q8. For the redox reaction,
\( MnO_{4}^{-} + C_{2}O_{4}^{2-} + H^{+} \rightarrow Mn^{2+} + CO_{2} + H_{2}O \)
The correct coefficients of the reactants for the balanced equation are Source: orcusprep.in

NEET 2018

medium

\( MnO_{4}^{-} = 16, C_{2}O_{4}^{2-} = 5, H^{+} = 2 \)

\( MnO_{4}^{-} = 2, C_{2}O_{4}^{2-} = 5, H^{+} = 16 \)

\( MnO_{4}^{-} = 2, C_{2}O_{4}^{2-} = 16, H^{+} = 5 \)

\( MnO_{4}^{-} = 5, C_{2}O_{4}^{2-} = 16, H^{+} = 2 \)

Q9. Hot concentrated sulphuric acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidizing behaviour? Source: orcusprep.in

NEET-II 2016

medium

\( Cu + 2H_{2}SO_{4} \rightarrow CuSO_{4} + SO_{2} + 2H_{2}O \)

\( S + 2H_{2}SO_{4} \rightarrow 3SO_{2} + 2H_{2}O \)

\( C + 2H_{2}SO_{4} \rightarrow CO_{2} + 2SO_{2} + 2H_{2}O \)

\( CaF_{2} + H_{2}SO_{4} \rightarrow CaSO_{4} + 2HF \)

Q10. (I) \( H_{2}O_{2} + O_{3} \rightarrow H_{2}O + 2O_{2} \)
(II) \( H_{2}O_{2} + Ag_{2}O \rightarrow 2Ag + H_{2}O + O_{2} \)
Role of hydrogen peroxide in the above reactions is respectively Source: orcusprep.in

NEET 2014

medium

oxidizing in (I) and reducing in (II)

reducing in (I) and oxidizing in (II)

reducing in (I) and (II)

oxidizing in (I) and (II)

Q11. The pair of compounds that can exist together is Source: orcusprep.in

NEET 2014

medium

\( FeCl_{3} \), \( SnCl_{2} \)

\( HgCl_{2} \), \( SnCl_{2} \)

\( FeCl_{2} \), \( SnCl_{2} \)

\( FeCl_{3} \), KI

Q12. A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the reaction which element undergoes maximum change in the oxidation number? Source: orcusprep.in

NEET 2012

medium

S

H

Cl

C

Q13. Oxidation numbers of P in \( PO_{4}^{3-} \), of S in \( SO_{4}^{2-} \) and that of Cr in \( Cr_{2}O_{7}^{2-} \) are respectively Source: orcusprep.in

NEET 2009

easy

+3, +6 and +5

+5, +3 and +6

–3, +6 and +6

+5, +6 and +6

Q14. Number of moles of \( MnO_{4}^{-} \) required to oxidize one mole of ferrous oxalate completely in acidic medium will be Source: orcusprep.in

NEET 2008

medium

7.5 moles

0.2 moles

0.6 moles

0.4 moles.

Q15. Which is the best description of the behaviour of bromine in the reaction given below?
\( H_{2}O + Br_{2} \rightarrow HOBr + HBr \) Source: orcusprep.in

NEET 2004

easy

Proton acceptor only

Both oxidised and reduced

Oxidised only

Reduced only

Q16. The oxidation states of sulphur in the anions \( SO_{3}^{2-} \), \( S_{2}O_{4}^{2-} \) and \( S_{2}O_{6}^{2-} \) follow the order Source: orcusprep.in

NEET 2003

easy

\( S_{2}O_{4}^{2-} < SO_{3}^{2-} < S_{2}O_{6}^{2-} \)

\( SO_{3}^{2-} < S_{2}O_{4}^{2-} < S_{2}O_{6}^{2-} \)

\( S_{2}O_{4}^{2-} < S_{2}O_{6}^{2-} < SO_{3}^{2-} \)

\( S_{2}O_{6}^{2-} < S_{2}O_{4}^{2-} < SO_{3}^{2-} \)

Q17. Oxidation state of Fe in \( Fe_{3}O_{4} \) is Source: orcusprep.in

NEET 1999

easy

\( \frac{5}{4} \)

\( \frac{4}{5} \)

\( \frac{3}{2} \)

\( \frac{8}{3} \)

Q18. Reaction of sodium thiosulphate with iodine gives Source: orcusprep.in

NEET 1996

medium

tetrathionate ion

sulphide ion

sulphate ion

sulphite ion.

Q19. The oxide, which cannot act as a reducing agent is Source: orcusprep.in

NEET 1995

easy

\( CO_{2} \)

\( ClO_{2} \)

\( NO_{2} \)

\( SO_{2} \)

Q20. Which substance is serving as a reducing agent in the following reaction?
\( 14H^{+} + Cr_{2}O_{7}^{2-} + 3Ni \rightarrow 7H_{2}O + 2Cr^{3+} + 3Ni^{2+} \) Source: orcusprep.in

NEET 1994

easy

\( H^{+} \)

\( Cr_{2}O_{7}^{2-} \)

\( H_{2}O \)

Ni

Q21. The oxidation state of I in \( H_{4}IO_{6}^{-} \) is Source: orcusprep.in

NEET 1994

easy

+ 1

– 1

+ 7

+ 5

Q22. Consider the change in oxidation state of bromine corresponding to different emf values as shown in the given diagram :
\( BrO_{4}^{-} \) \( \xrightarrow{1.82 \text{ V}} \) \( BrO_{3}^{-} \) \( \xrightarrow{1.5 \text{ V}} \) \( HBrO \)
\( Br_{2} \) \( \xrightarrow{1.0652 \text{ V}} \) \( Br^{-} \) \( \xleftarrow{1.595 \text{ V}} \)
Then the species undergoing disproportionation is Source: orcusprep.in

NEET 2018

hard

\( BrO_{3}^{-} \)

\( BrO_{4}^{-} \)

\( Br_{2} \)

\( HBrO \)

Q23. Which reaction is not a redox reaction? Source: orcusprep.in

NEET 2024

easy

\( Zn + CuSO_{4} \rightarrow ZnSO_{4} + Cu \)

\( 2KClO_{3} + I_{2} \rightarrow 2KIO_{3} + Cl_{2} \)

\( H_{2} + Cl_{2} \rightarrow 2HCl \)

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

Q24. On balancing the given redox reaction,
\( aCr_{2}O_{7}^{2-}(aq) + bSO_{3}^{2-}(aq) + c H^{+}(aq) \rightarrow 2aCr^{3+}(aq) + bSO_{4}^{2-}(aq) + H_{2}O(l) \)
the coefficients a, b and c are found to be respectively Source: orcusprep.in

NEET 2023

medium

1, 8, 3

8, 1, 3

1, 3, 8

3, 8, 1

Q25. Which of the following reactions is a metal displacement reaction? Choose the right option. Source: orcusprep.in

NEET 2021

easy

\( 2Pb(NO_{3})_{2} \rightarrow 2PbO + 4NO_{2} + O_{2} \uparrow \)

\( 2KClO_{3} \rightarrow 2KCl + 3O_{2} \uparrow \)

\( Cr_{2}O_{3} + 2Al \rightarrow Al_{2}O_{3} + 2Cr \)

\( Fe + 2HCl \rightarrow FeCl_{2} + H_{2} \uparrow \)

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Chemistry - Redox Reaction-PYQ

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Chemistry - Redox Reaction-PYQ

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