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Redox Reactions

22 Questions Start NEET Test
All Exams NEET AIIMS
2026 Q1 NEET MCQ
28 Jun 2026

In an acidic medium, 10 mL of 0.25 M oxalic acid is titrated with $\mathrm{KMnO}_4$ solution. If the volume of $\mathrm{KMnO}_4$ solution required to reach end point is 10 mL , the strength of the $\mathrm{KMnO}_4$ solution is

A.

0.15 M

B.

0.10 M

C.

0.20 M

D.

0.25 M

2026 Q2 NEET MCQ
28 Jun 2026

The correct decreasing order of oxidation state of the $\underline{\mathrm{underlined\, atom}}$ in each molecule is

A.

$ \underline{\mathrm{P}}_4 \mathrm{O}_6>\underline{\mathrm{Cl}}_2 \mathrm{O}_7>\underline{\mathrm{A}}\mathrm{l}\mathrm{H}_3 $

B.

$ \underline{\mathrm{P}}_4 \mathrm{O}_{10}>\underline{\mathrm{S}}O_3>\mathrm{H}_2 \underline{\mathrm{O}} $

C.

$ \underline{\mathrm{N}}_2 \mathrm{O}_5>\underline{\mathrm{Al}}_2 \mathrm{O}_3>\mathrm{H}_2 \underline{\mathrm{~S}} $

D.

$ \underline{\mathrm{Pb}}O_2>\underline{\mathrm{N}}_2 \mathrm{O}_3>\underline{\mathrm{S}}O_3 $

2025 Q3 NEET MCQ
10 Mar 2026

Consider the following compounds :

${\mathrm{\underline{K}O}}_2, \mathrm{H}_2 \underline{\mathrm{O}}_2$ and $\mathrm{H}_2 \underline{S }O_4$

The oxidation state of the underlined elements in them are, respectively,

A.
$+1,-2$, and +4
B.
$+4,-4$, and +6
C.
$+1,-1$, and +6
D.
$+2,-2$, and +6
2024 Q4 NEET MCQ
10 Mar 2026

The oxidation states not shown by Mn in given reaction is :

$ 3 \mathrm{MnO}_4^{2-}+4 \mathrm{H}^{+} \longrightarrow 2 \mathrm{MnO}_4^{-}+\mathrm{MnO}_2+2 \mathrm{H}_2 \mathrm{O} $

A. +6

B. +2

C. +4

D. +7

E. +3

Choose the most appropriate answer from the options given below :

A.
D and E only
B.
B and D only
C.
A and B only
D.
B and E only
2024 Q5 NEET MCQ
10 Mar 2026

Which reaction is NOT a redox reaction?

A.
$\mathrm{Zn}+\mathrm{CuSO}_4 \rightarrow \mathrm{ZnSO}_4+\mathrm{Cu}$
B.
$2 \mathrm{KClO}_3+\mathrm{I}_2 \rightarrow 2 \mathrm{KIO}_3+\mathrm{Cl}_2$
C.
$\mathrm{H}_2+\mathrm{Cl}_2 \rightarrow 2 \mathrm{HCl}$
D.
$\mathrm{BaCl}_2+\mathrm{Na}_2 \mathrm{SO}_4 \rightarrow \mathrm{BaSO}_4+2 \mathrm{NaCl}$
2023 Q6 NEET MCQ
10 Mar 2026

The correct option for a redox couple is:

A.
Both are oxidised forms involving same element.
B.
Both are reduced forms involving same element.
C.
Both the reduced and oxidised forms involve same element.
D.
Cathode and anode together.
2023 Q7 NEET MCQ
10 Mar 2026

On balancing the given redox reaction,

$\mathrm{aCr}_{2} \mathrm{O}_{7}^{2-}+\mathrm{bSO}_{3}^{2-}(\mathrm{aq})+\mathrm{cH}^{+}(\mathrm{aq}) \rightarrow 2 \mathrm{aCr}^{3+}(\mathrm{aq})+\mathrm{bSO}_{4}^{2-}(\mathrm{aq})+\frac{\mathrm{c}}{2} \mathrm{H}_{2} \mathrm{O}(\ell)$

the coefficients $\mathrm{a}, \mathrm{b}$ and $\mathrm{c}$ are found to be, respectively -

A.
3, 8, 1
B.
1, 8, 3
C.
8, 1, 3
D.
1, 3, 8
2022 Q8 NEET MCQ
10 Mar 2026

Which of the following reactions is a decomposition redox reaction?

A.
P4(s) + 3OH$-$(aq) + 3H2O(l) $\to$ PH3(g) + 3H2PO$_2^ - $(aq)
B.
2Pb(NO3)2(s) $\to$ 2PbO(s) + 4NO2(g) + O2(g)
C.
N2(g) + O2(g) $\to$ 2NO(g)
D.
Cl2(g) + 2OH$-$(aq) $\to$ ClO$-$(aq) + Cl$-$(aq) + 4H2O(l)
2020 Q9 NEET MCQ
10 Mar 2026
What is the change in oxidation number of carbon in the following reaction?
CH4(g) + 4Cl2(g) $ \to $ CCl4(l) + 4HCl(g)
A.
0 to + 4
B.
$ - $4 to + 4
C.
0 to $ - $ 4
D.
+ 4 to + 4
2019 Q10 NEET MCQ
10 Mar 2026
Which of the following reactions are disproportionation reaction?

(a) 2Cu+ $ \to $ Cu2+ + Cu0
(b) 3MnO42- + 4H+ $ \to $ 2MnO4- + MnO2 + 2H2O
(c) 2KMnO4 $\buildrel \Delta \over \longrightarrow $ K2MnO4 + MnO2 + O2
(d) 2MnO4- + 3Mn2+ + 2H2O $ \to $ 5MnO2 + 4${H^ \oplus }$

Select the correct option from the following :
A.
(a), (c) and (d)
B.
(a) and (b) only
C.
(a) and (d) only
D.
(a), (b) and (c)
2018 Q11 NEET MCQ
10 Mar 2026
The correct order of N-compounds in its decreasing order of oxidation states is
A.
HNO3 , NO, N2 , NH4Cl
B.
HNO3 , NO, NH4Cl, N2
C.
HNO3 , NH4Cl, NO, N
D.
NH4Cl, N2 , NO, HNO3
2018 Q12 NEET MCQ
10 Mar 2026
For the redox reaction,
MnO4– + C2O4 2– + H+ $ \to $ Mn2+ + CO2 + H2O
The correct coefficients of the reactants for the balanced equation are
A.
MnO4- C2O42- H+
16 5 2
B.
MnO4- C2O42- H+
2 5 16
C.
MnO4- C2O42- H+
2 16 5
D.
MnO4- C2O42- H+
5 16 2
2016 Q13 NEET MCQ
10 Mar 2026
Hot concentrated sulphate acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidizing behaviour?
A.
Cu + 2H2SO4 $ \to $ CuSO4 + SO2 + 2H2O
B.
S + 2H2SO4 $ \to $ 3SO2 + 2H2O
C.
C + 2H2SO4 $ \to $ CO2 + 2SO2 + 2H2O
D.
CaF2 + H2SO4 $ \to $ CaSO4 + 2HF
2014 Q14 NEET MCQ
10 Mar 2026
(I)   H2O2 + O3 $ \to $ H2O + 2O2
(II)   H2O2 + Ag2O $ \to $ 2Ag + H2O + O2
Role of Hydrogen peroxide in the above reactions is respectvely
A.
oxidizing in (I) and reducing in (II)
B.
reducing in (I) and oxidizing (II)
C.
reducing in (I) and (II)
D.
oxidizing in (I) and (II)
2014 Q15 NEET MCQ
10 Mar 2026
In acidic medium, H2O2 changes Cr2O72- to CrO5 which has two

($-$O$-$O$-$) bonds. Oxidation state of Cr in CrO5 is
A.
+5
B.
+3
C.
+6
D.
$-$10
2014 Q16 NEET MCQ
10 Mar 2026
The pair of compounds that can exist together is
A.
FeCl3, SnCl2
B.
HgCl2, SnCl2
C.
FeCl2, SnCl2
D.
FeCl3, KI
2012 Q17 NEET MCQ
10 Mar 2026
When Cl2 gas reacts with hot and concentrated sodium hydroxide solution, the oxidation number of chlorine changes from
A.
zero to +1 and zero to $-$5
B.
zero to $-$1 and zero to +5
C.
zero to $-$1 and zero to +3
D.
zero to +1 and zero to $-$3
2012 Q18 NEET MCQ
10 Mar 2026
A mixture of potassium chlorate, oxalic acid and sulphuric acid is heated. During the reaction which element undergoes maximum change in the oxidation number?
A.
S
B.
H
C.
Cl
D.
C
2009 Q19 NEET MCQ
10 Mar 2026
Oxidation numbers of P in PO$_4^{3 - }$, of S in SO$_4^{2 - }$ and that of Cr in Cr2O$_7^{2 - }$ are respectively
A.
+3, +6 and +5
B.
+5, +3 and +6
C.
$-$3, +6 and + 6
D.
+5, +6 and +6
2008 Q20 NEET MCQ
10 Mar 2026
Number of moles of MnO$_4^{ - }$ required to oxidize one mole of ferrous oxalate completely in acidic medium will be
A.
7.5 moles
B.
0.2 moles
C.
0.6 moles
D.
0.4 moles
2004 Q21 NEET MCQ
10 Mar 2026
Which is the best description of the behaviour of bromine in the reaction given below?
H2O + Br2 $ \to $ HOBr + HBr
A.
Proton acceptor only
B.
Both oxidised and reduced
C.
Oxidised only
D.
Reduced only
2003 Q22 NEET MCQ
10 Mar 2026
The oxidation states of sulphur in the anions

SO3${_3^{2 - }}$, S2O${_4^{2 - }}$ and S2O${_6^{2 - }}$ follow the order
A.
S2O${_4^{2 - }}$ < SO${_3^{2 - }}$ < S2O${_6^{2 - }}$
B.
SO${_3^{2 - }}$ < S2O${_4^{2 - }}$ < S2O${_6^{2 - }}$
C.
S2O${_4^{2 - }}$ < S2O${_6^{2 - }}$ < SO${_3^{2 - }}$
D.
S2O${_6^{2 - }}$ < S2O${_4^{2 - }}$ < SO${_3^{2 - }}$