Redox Reactions · JEE Main previous year questions

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2022 11 questions

Q672022 · 29 Jul 2022 · Shift 1
In neutral or faintly alkaline medium, $KMn O_{4}$ being a powerful oxidant can oxidize, thiosulphate almost quantitatively, to sulphate. In this reaction overall change in oxidation state of manganese will be :
1. A.5
2. B.1
3. C.0
4. D.3
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Answer: D
Q872022 · 28 Jul 2022 · Shift 1· Numerical answer
The disproportionation of $MnO_{4}^{2 -}$ in acidic medium resulted in the formation of two manganese compounds A and B. If the oxidation state of $Mn$ in B is smaller than that of A, then the spin-only magnetic moment ( $μ$ ) value of B in BM is _________. (Nearest integer)
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Answer: 4
Q892022 · 28 Jul 2022 · Shift 2· Numerical answer
On reaction with stronger oxidizing agent like $KI O_{4}$ , hydrogen peroxide oxidizes with the evolution of $O_{2}$ . The oxidation number of $I$ in $KI O_{4}$ changes to ____.
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Answer: 5
Q752022 · 27 Jul 2022 · Shift 1
Given below are two statements. Statement I : Hydrogen peroxide can act as an oxidizing agent in both acidic and basic conditions. Statement II : Density of hydrogen peroxide at $298 K$ is lower than that of $D_{2} O$ . In the light of the above statements, choose the correct answer from the options given below.
1. A.Both Statement I and Statement II are true.
2. B.Both Statement I and Statement II are false.
3. C.Statement I is true but Statement II is false.
4. D.Statement I is false but Statement II is true.
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Answer: C
Q642022 · 26 Jul 2022 · Shift 1
Which of the given reactions is not an example of disproportionation reaction?
1. A. $2 H_{2} O_{2} \to 2 H_{2} O + O_{2}$
2. B. $2 N O_{2} + H_{2} O \to HN O_{3} + HN O_{2}$
3. C. $Mn O_{4}^{-} + 4 H^{+} + 3 e^{-} \to Mn O_{2} + 2 H_{2} O$
4. D. $3 Mn O_{4}^{2 -} + 4 H^{+} \to 2 Mn O_{4}^{-} + Mn O_{2} + 2 H_{2} O$
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Answer: C
Q892022 · 27 Jun 2022 · Shift 2· Numerical answer
BeO reacts with HF in presence of ammonia to give [A] which on thermal decomposition produces [B] and ammonium fluoride. Oxidation state of Be in [A] is ____________.
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Answer: 2
Q652022 · 26 Jun 2022 · Shift 1
Choose the correct stability order of group 13 elements in their + 1 oxidation state :
1. A.Al < Ga < In < Tl
2. B.Tl < In < Ga < Al
3. C.Al < Ga < Tl < In
4. D.Al < Tl < Ga < In
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Answer: A
Q652022 · 26 Jun 2022 · Shift 2
Which one of the following is an example of disproportionation reaction ?
1. A. $3 Mn O_{4}^{2 -} + 4 H^{+} \to 2 Mn O_{4}^{-} + Mn O_{2} + 2 H_{2} O$
2. B. $Mn O_{4}^{-} + 4 H^{+} + 4 e^{-} \to Mn O_{2} + 2 H_{2} O$
3. C. $10 I^{-} + 2 Mn O_{4}^{-} + 16 H^{+} \to 2 M n^{2 +} + 8 H_{2} O + 5 I_{2}$
4. D. $8 Mn O_{4}^{-} + 3 S_{2} O_{3}^{2 -} + H_{2} O \to 8 Mn O_{2} + 6 S O_{4}^{2 -} + 2 O H^{-}$
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Answer: A
Q662022 · 26 Jun 2022 · Shift 2
The most common oxidation state of Lanthanoid elements is +3. Which of the following is likely to deviate easily from +3 oxidation state?
1. A.Ce (At. No. 58)
2. B.La (At. No. 57)
3. C.Lu (At. No. 71)
4. D.Gd (At. No. 64)
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Answer: A
Q662022 · 25 Jun 2022 · Shift 1
Among the following, which is the strongest oxidizing agent?
1. A. $Mn^{3 +}$
2. B. $Fe^{3 +}$
3. C. $Ti^{3 +}$
4. D. $Cr^{3 +}$
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Answer: A
Q842022 · 24 Jun 2022 · Shift 2· Numerical answer
Manganese (VI) has ability to disproportionate in acidic solution. The difference in oxidation states of two ions it forms in acidic solution is ____________.
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Answer: 3