Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Redox Reactions question

2025 · 29 Jan · Shift 2 · Q5
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Chemistry
  4. /Redox Reactions
  5. /2025 · 29 Jan · Shift 2 · Q5

Redox Reactions question

2025 · 29 Jan · Shift 2 · Q5

JEE MainChemistryRedox ReactionsMCQ+4 / −1
0.1 M solution of KI reacts with excess of H2SO4\mathrm{H}_2 \mathrm{SO}_4H2​SO4​ and KIO3\mathrm{KIO}_3KIO3​ solutions. According to equation 5I−+IO3−+6H+→3I2+3H2O5 \mathrm{I}^{-}+\mathrm{IO}_3^{-}+6 \mathrm{H}^{+} \rightarrow 3 \mathrm{I}_2+3 \mathrm{H}_2 \mathrm{O}5I−+IO3−​+6H+→3I2​+3H2​O Identify the correct statements : (A) 200 mL of KI solution reacts with 0.004 mol of KIO3\mathrm{KIO}_3KIO3​(B) 200 mL of KI solution reacts with 0.006 mol of H2SO4\mathrm{H}_2 \mathrm{SO}_4H2​SO4​(C) 0.5 L of KI solution produced 0.005 mol of I2\mathrm{I}_2I2​(D) Equivalent weight of KIO3\mathrm{KIO}_3KIO3​ is equal to ( Molecular weight 5\frac{\text { Molecular weight }}{5}5 Molecular weight ​ ) Choose the correct answer from the options given below :
  1. A
    (C) and (D) only
  2. B
    (A) and (B) only
  3. C
    (B) and (C) only
  4. D
    (A) and (D) only
View written solutionFree

Correct answer: D

  1. Given reaction

5I−+IO3−+6H+→3I2+3H2O5\mathrm{I}^- + \mathrm{IO}_3^- + 6\mathrm{H}^+ \rightarrow 3\mathrm{I}_2 + 3\mathrm{H}_2\mathrm{O}5I−+IO3−​+6H+→3I2​+3H2​O

We evaluate each statement using the stoichiometric coefficients.


  1. Moles of KI in the given solution volumes

The KI solution is 0.1 M0.1\,\mathrm{M}0.1M.

  • For 200 mL=0.2 L200\,\mathrm{mL} = 0.2\,\mathrm{L}200mL=0.2L: n(KI)=M×V=0.1×0.2=0.02 moln(\mathrm{KI}) = M\times V = 0.1\times 0.2 = 0.02\,\mathrm{mol}n(KI)=M×V=0.1×0.2=0.02mol Since KI gives one I−\mathrm{I}^-I− per mole, n(I−)=0.02 moln(\mathrm{I}^-) = 0.02\,\mathrm{mol}n(I−)=0.02mol

  • For 0.5 L0.5\,\mathrm{L}0.5L: n(KI)=0.1×0.5=0.05 moln(\mathrm{KI}) = 0.1\times 0.5 = 0.05\,\mathrm{mol}n(KI)=0.1×0.5=0.05mol Hence, n(I−)=0.05 moln(\mathrm{I}^-) = 0.05\,\mathrm{mol}n(I−)=0.05mol


  1. Check statement (A)

From the reaction, 5I−:1IO3−5\mathrm{I}^- : 1\mathrm{IO}_3^-5I−:1IO3−​

So for 0.020.020.02 mol I−\mathrm{I}^-I− required moles of IO3−\mathrm{IO}_3^-IO3−​ are n(IO3−)=0.025=0.004 moln(\mathrm{IO}_3^-) = \frac{0.02}{5} = 0.004\,\mathrm{mol}n(IO3−​)=50.02​=0.004mol

Since KIO3\mathrm{KIO}_3KIO3​ provides one IO3−\mathrm{IO}_3^-IO3−​ per mole, n(KIO3)=0.004 moln(\mathrm{KIO}_3)=0.004\,\mathrm{mol}n(KIO3​)=0.004mol

So (A) is correct.


  1. Check statement (B)

From the reaction, 5I−:6H+5\mathrm{I}^- : 6\mathrm{H}^+5I−:6H+

For 0.020.020.02 mol I−\mathrm{I}^-I−, n(H+)=65×0.02=0.024 moln(\mathrm{H}^+) = \frac{6}{5}\times 0.02 = 0.024\,\mathrm{mol}n(H+)=56​×0.02=0.024mol

Now H2SO4\mathrm{H}_2\mathrm{SO}_4H2​SO4​ gives 2H+2\mathrm{H}^+2H+ per mole, so required moles of sulfuric acid are n(H2SO4)=0.0242=0.012 moln(\mathrm{H}_2\mathrm{SO}_4)=\frac{0.024}{2}=0.012\,\mathrm{mol}n(H2​SO4​)=20.024​=0.012mol

But the statement says 0.0060.0060.006 mol.

So (B) is incorrect.


  1. Check statement (C)

From the reaction, 5I−→3I25\mathrm{I}^- \rightarrow 3\mathrm{I}_25I−→3I2​

For 0.050.050.05 mol I−\mathrm{I}^-I−, n(I2)=35×0.05=0.03 moln(\mathrm{I}_2)=\frac{3}{5}\times 0.05=0.03\,\mathrm{mol}n(I2​)=53​×0.05=0.03mol

But the statement says 0.0050.0050.005 mol.

So (C) is incorrect.


  1. Check statement (D)

In KIO3\mathrm{KIO}_3KIO3​, iodine in IO3−\mathrm{IO}_3^-IO3−​ changes from oxidation state +5+5+5 to 000 in I2\mathrm{I}_2I2​.

Thus, 1 mole of KIO3\mathrm{KIO}_3KIO3​ gains 555 electrons.

Therefore, n-factor of KIO3\mathrm{KIO}_3KIO3​ is 555, so equivalent weight is Equivalent weight=Molecular weight5\text{Equivalent weight} = \frac{\text{Molecular weight}}{5}Equivalent weight=5Molecular weight​

So (D) is correct.


  1. Final conclusion

Correct statements are: (A) and (D)\boxed{(A) \text{ and } (D)}(A) and (D)​

Hence the correct option is D\boxed{\text{D}}D​

PreviousNext

More from Redox Reactions

  • Which of the following reactions are disproportionation reactions? (A) Cu+→Cu2++Cu(B) 3MnO42−​+4H+⟶2MnO4−​+MnO2​+2H2​O…2024 · MCQ
  • In acidic medium, K2​Cr2​O7​ shows oxidising action as represented in the half reaction: Cr2​O7​2−+XH++Ye⊖→2 A+ZH2​O…2024 · MCQ
  • Only 2 mL of KMnO4​ solution of unknown molarity is required to reach the end point of a titration of 20 mL of oxalic acid (2M) in acidic medium. The molarity of KMnO4​ solution…2024 · Numerical
  • When MnO2​ and H2​SO4​ is added to a salt (A), the greenish yellow gas liberated as salt (A) is :2024 · MCQ
  • The number of ions from the following that are expected to behave as oxidising agent is : Sn4+,Sn2+,Pb2+,Tl3+,Pb4+,Tl+2024 · MCQ
  • Match List I with List II. Choose the correct answer from the options given below : Includes table2024 · MCQ
  • Thiosulphate reacts differently with iodine and bromine in the reactions given below: ​2 S2​O32−​+I2​→S4​O62−​+2I−S2​O32−​+5Br2​+5H2​O→2SO42−​+4Br−+10H+​…2024 · MCQ
  • Which of the following cannot function as an oxidising agent?2024 · MCQ