Redox Reactions · JEE Main previous year questions

2025 7 questions

1. Q742025 · 4 Apr 2025 · Shift 1· Numerical answer

   $\mathrm{KMn}{\mathrm{O}}_4$ acts as an oxidising agent in acidic medium. ' X ' is the difference between the oxidation states of Mn in reactant and product. ' Y ' is the number of ' d ' electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of $\mathrm{X}+\mathrm{Y}$ is ____.

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   Answer: 10

2. Q582025 · 3 Apr 2025 · Shift 1

   Given below are two statements : Statement I : The N - N single bond is weaker and longer than that of P - P single bond. Statement II : Compounds of group 15 elements in +3 oxidation states readily undergo disproportionation reactions. 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.Both Statement I and Statement II are true
   3. C.Both Statement I and Statement II are false
   4. D.Statement I is true but Statement II is false
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   Answer: C

3. Q602025 · 3 Apr 2025 · Shift 2

   Given below are two statements: Statement I : ${\mathrm{CrO}}_3$ is a stronger oxidizing agent than ${\mathrm{MoO}}_3$ Statement II : $\mathrm{Cr}(\mathrm{VI})$ is more stable than $\mathrm{Mo}(\mathrm{VI})$ In the light of the above statements, choose the correct answer from the options given below

   1. A.Statement I is true but Statement II is false
   2. B.Both Statement I and Statement II are true
   3. C.Both Statement I and Statement II are false
   4. D.Statement I is false but Statement II is true
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   Answer: A

4. Q602025 · 28 Jan 2025 · Shift 1

   Consider the following elements $\mathrm{In},\mathrm{Tl},\mathrm{Al},\mathrm{Pb},\mathrm{Sn}$ and $\mathrm{Ge}$ . The most stable oxidation states of elements with highest and lowest first ionisation enthalpies, respectively, are

   1. A.$+4$ and $+1$
   2. B.$+4$ and $+3$
   3. C.$+1$ and $+4$
   4. D.$+2$ and $+3$
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   Answer: B

5. Q662025 · 28 Jan 2025 · Shift 1

   Match the List - I with List - II $$\begin{array}{llll}& \text{List - I}& & \text{List - II}\\ & \text{(Redox Reaction)}& & \text{(Type of Redox Reaction)}\\ \text{(A)}& \mathrm{C}{\mathrm{H}}_{4(\mathrm{g})}+2{\mathrm{O}}_{2(\mathrm{g})}\stackrel{\mathrm{\Delta }}{\to }\mathrm{C}{\mathrm{O}}_{2(\mathrm{g})}+2{\mathrm{H}}_2{\mathrm{O}}_{(\mathrm{l})}& \text{(I)}& \text{Disproportionation reaction}\\ \text{(B)}& 2Na{\mathrm{H}}_{(\mathrm{s})}\stackrel{\mathrm{\Delta }}{\to }2N{\mathrm{a}}_{(\mathrm{s})}+{\mathrm{H}}_{2(\mathrm{g})}& \text{(II)}& \text{Combination reaction}\\ \text{(C)}& {\mathrm{V}}_2{\mathrm{O}}_{5(\mathrm{s})}+5C{\mathrm{a}}_{(\mathrm{s})}\stackrel{\mathrm{\Delta }}{\to }2{\mathrm{V}}_{(\mathrm{s})}+5Ca{\mathrm{O}}_{(\mathrm{s})}& \text{(III)}& \text{Decomposition reaction}\\ \text{(D)}& 2{\mathrm{H}}_2{\mathrm{O}}_{2(\mathrm{aq})}\stackrel{\mathrm{\Delta }}{\to }2{\mathrm{H}}_2{\mathrm{O}}_{(\mathrm{l})}+{\mathrm{O}}_{2(\mathrm{g})}& \text{(IV)}& \text{Displacement reaction}\end{array}$$ Choose the correct answer from the options given below:

   1. A.A-III, B-IV, C-I, D-II
   2. B.A-IV, B-I, C-II, D-III
   3. C.A-II, B-III, C-I, D-IV
   4. D.A-II, B-III, C-IV, D-I
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   Answer: D

6. Q702025 · 24 Jan 2025 · Shift 1

   Which of the following ions is the strongest oxidizing agent? (Atomic Number of $\mathrm{Ce}=58,\mathrm{Eu}=63,\mathrm{Tb}=65,\mathrm{Lu}=71$)

   1. A.$\mathrm{L}{\mathrm{u}}^{3+}$
   2. B.$\mathrm{E}{\mathrm{u}}^{2+}$
   3. C.$\mathrm{T}{\mathrm{b}}^{4+}$
   4. D.$\mathrm{C}{\mathrm{e}}^{3+}$
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   Answer: C

7. Q572025 · 24 Jan 2025 · Shift 2

   Based on the data given below : ${\mathrm{E}}_{\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7^{2-}/C{\mathrm{r}}^{3+}}^{\circ }=1.33\text{ V}{\mathrm{E}}_{\mathrm{C}{\mathrm{l}}_2/C{\mathrm{l}}^{(-)}}^{\circ }=1.36\text{ V}$ ${\mathrm{E}}_{\mathrm{Mn}{\mathrm{O}}_4^{-}/M{\mathrm{n}}^{2+}}^0=1.51\text{ V}{\mathrm{E}}_{\mathrm{C}{\mathrm{r}}^{3+}/Cr}^{\circ }=-0.74\text{ V}$ the strongest reducing agent is :

   1. A.$\mathrm{C}{\mathrm{l}}^{-}$
   2. B.$\mathrm{Mn}{\mathrm{O}}_4^{-}$
   3. C.$\mathrm{Cr}$
   4. D.$\mathrm{M}{\mathrm{n}}^{2+}$
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   Answer: C