Redox Reactions · JEE Main previous year questions

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2024 18 questions

Q632024 · 8 Apr 2024 · Shift 1
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R: Assertion A: The stability order of +1 oxidation state of $Ga, In$ and $Tl$ is $Ga < In < Tl$ . Reason R: The inert pair effect stabilizes the lower oxidation state down the group. In the light of the above statements, choose the correct answer from the options given below:
1. A.A is true but R is false.
2. B.Both A and R are true but R is NOT the correct explanation of A.
3. C.A is false but R is true.
4. D.Both A and R are true and R is the correct explanation of A.
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Answer: D
Q662024 · 8 Apr 2024 · Shift 1
Among the following halogens $F_{2}, C l_{2}, B r_{2}$ and $I_{2}$ Which can undergo disproportionation reactions?
1. A. $F_{2}$ and $C l_{2}$
2. B. $C l_{2}, B r_{2}$ and $I_{2}$
3. C.Only $I_{2}$
4. D. $F_{2}, C l_{2}$ and $B r_{2}$
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Answer: B
Q742024 · 8 Apr 2024 · Shift 2
Given below are two statements : Statement (I) : Fusion of $Mn O_{2}$ with $KOH$ and an oxidising agent gives dark green $K_{2} Mn O_{4}$ . Statement (II) : Manganate ion on electrolytic oxidation in alkaline medium gives permanganate ion. In the light of the above statements, choose the correct answer from the options given below :
1. A.Statement I is false but Statement II is true
2. B.Statement I is true but Statement II is false
3. C.Both Statement I and Statement II are false
4. D.Both Statement I and Statement II are true
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Answer: D
Q612024 · 6 Apr 2024 · Shift 2
The number of ions from the following that are expected to behave as oxidising agent is : $Sn^{4 +}, Sn^{2 +}, Pb^{2 +}, Tl^{3 +}, Pb^{4 +}, Tl^{+}$
1. A.3
2. B.4
3. C.2
4. D.1
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Answer: C
Q652024 · 6 Apr 2024 · Shift 2
Match List I with List II. | LIST I (Reaction) | LIST II (Type of redox reaction) | | :--- | :--- | | A. $N_{2 (g)} + O_{2 (g)} \to 2 NO_{(g)}$ | I. Decomposition | | B. $2 Pb (NO_{3})_{2 (s)} \to 2 PbO_{(s)} + 4 NO_{2 (g)} + O_{2 (g)}$ | II. Displacement | | C. $2 Na_{(s)} + 2 H_{2} O_{(l)} \to 2 NaOH_{(a q .)} + H_{2 (g)}$ | III. Disproportionation | | D. $2 NO_{2 (g)} + 2 OH_{(a q .)}^{-} \to NO_{2 (a q .)}^{-} + NO_{3 (a q .)}^{-} + H_{2} O_{(l)}$ | IV. Combination | Choose the correct answer from the options given below :
1. A.(A)-(IV), (B)-(I), (C)-(II), (D)-(III)
2. B.(A)-(I), (B)-(II), (C)-(III), (D)-(IV)
3. C.(A)-(II), (B)-(III), (C)-(IV), (D)-(I)
4. D.(A)-(III), (B)-(II), (C)-(I), (D)-(IV)
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Answer: A
Q682024 · 4 Apr 2024 · Shift 1
The element which shows only one oxidation state other than its elemental form is :
1. A.Nickel
2. B.Titanium
3. C.Cobalt
4. D.Scandium
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Answer: D
Q612024 · 1 Feb 2024 · Shift 1
Which of the following reactions are disproportionation reactions? (A) $C u^{+} \to C u^{2 +} + Cu$ (B) $3Mn O_{4}^{2 -} + 4 H^{+} ⟶ 2Mn O_{4}^{-} + Mn O_{2} + 2 H_{2} O$ (C) $2KMn O_{4} ⟶ K_{2} Mn O_{4} + Mn O_{2} + O_{2}$ (D) $2Mn O_{4}^{-} + 3M n^{2 +} + 2 H_{2} O ⟶ 5Mn O_{2} + 4 H^{+}$ Choose the correct answer from the options given below :
1. A.(A), (B)
2. B.(A), (D)
3. C.(B), (C), (D)
4. D.(A), (B), (C)
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Answer: A
Q872024 · 1 Feb 2024 · Shift 1· Numerical answer
The lowest oxidation number of an atom in a compound $A_{2} B$ is $- 2$ . The number of electrons in its valence shell is ________ .
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Answer: 6
Q692024 · 1 Feb 2024 · Shift 2
Given below are two statements : Statement (I) : Dimethyl glyoxime forms a six-membered covalent chelate when treated with $NiC l_{2}$ solution in presence of $N H_{4} OH$ . Statement (II) : Prussian blue precipitate contains iron both in $(+ 2)$ and $(+ 3)$ oxidation states. In the light of the above statements, choose the most appropriate answer from the options given below :
1. A.Statement I is false but Statement II is true
2. B.Both Statement I and Statement II are true
3. C.Statement I is true but Statement II is false
4. D.Both Statement I and Statement II are false
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Answer: A
Q722024 · 1 Feb 2024 · Shift 2
The strongest reducing agent among the following is :
1. A. $Sb H_{3}$
2. B. $N H_{3}$
3. C. $Bi H_{3}$
4. D. $P H_{3}$
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Answer: C
Q662024 · 31 Jan 2024 · Shift 2
Given below are two statements: Statement I : $S_{8}$ solid undergoes disproportionation reaction under alkaline conditions to form $S^{2 -}$ and $S_{2} O_{3}^{2 -}$ . Statement II : $Cl O_{4}^{-}$ can undergo disproportionation reaction under acidic condition. In the light of the above statements, choose the most appropriate answer from the options given below :
1. A.Statement I is correct but statement II is incorrect
2. B.Both statement I and statement II are incorrect
3. C.Statement I is incorrect but statement II is correct
4. D.Both statement I and statement II are correct
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Answer: A
Q792024 · 30 Jan 2024 · Shift 1
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : There is a considerable increase in covalent radius from $N$ to $P$ . However from As to Bi only a small increase in covalent radius is observed. Reason (R) : Covalent and ionic radii in a particular oxidation state increases down the group. In the light of the above statements, choose the most appropriate answer from the options given below:
1. A.(A) is false but (R) is true
2. B.Both (A) and (R) are true and (R) is the correct explanation of (A)
3. C.Both (A) and (R) are true but (R) is not the correct explanation of (A)
4. D.(A) is true but (R) is false
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Answer: C
Q672024 · 29 Jan 2024 · Shift 1
Chlorine undergoes disproportionation in alkaline medium as shown below : $aC l_{2 (g)} + bO H_{(aq)}^{-} \to cCl O_{(aq)}^{-} + dC l_{(aq)}^{-} + e H_{2} O_{(l)}$ The values of $a, b, c$ and $d$ in a balanced redox reaction are respectively :
1. A. $3, 4, 4$ and $2$
2. B. $1, 2, 1$ and $1$
3. C. $2, 4, 1$ and $3$
4. D. $2, 2, 1$ and $3$
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Answer: B
Q632024 · 29 Jan 2024 · Shift 2
Which of the following acts as a strong reducing agent? (Atomic number: $Ce = 58, Eu = 63, Gd = 64, Lu = 71$ )
1. A. $Eu^{2 +}$
2. B. $Gd^{3 +}$
3. C. $Lu^{3 +}$
4. D. $Ce^{4 +}$
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Answer: A
Q632024 · 27 Jan 2024 · Shift 1
Element not showing variable oxidation state is :
1. A.Bromine
2. B.Iodine
3. C.Chlorine
4. D.Fluorine
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Answer: D
Q902024 · 27 Jan 2024 · Shift 1· Numerical answer
From the given list, the number of compounds with +4 oxidation state of Sulphur _______. $SO_{3}, H_{2} SO_{3}, SOCl_{2}, SF_{4}, BaSO_{4}, H_{2} S_{2} O_{7}$
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Answer: 3
Q642024 · 27 Jan 2024 · Shift 2
Given below are two statements : Statement (I) : Oxygen being the first member of group 16 exhibits only -2 oxidation state. Statement (II) : Down the group 16 stability of +4 oxidation state decreases and +6 oxidation state increases. In the light of the above statements, choose the most appropriate answer from the options given below :
1. A.Statement I is correct but Statement II is incorrect
2. B.Both Statement I and Statement II are incorrect
3. C.Statement I is incorrect but Statement II is correct
4. D.Both Statement I and Statement II are correct
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Answer: B
Q732024 · 27 Jan 2024 · Shift 2
Which of the following cannot function as an oxidising agent?
1. A. $SO_{4}^{2 -}$
2. B. $MnO_{4}^{-}$
3. C. $N^{3 -}$
4. D. $BrO_{3}^{-}$
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Answer: C