Redox Reactions · JEE Main previous year questions

2017 3 questions

1. Q882017 · 9 Apr 2017 · Shift 1

   The number of P–OH bonds and the oxidation state of phosphorus atom in pyrophosphoric acid (${\mathrm{H}}_4{\mathrm{P}}_2{\mathrm{O}}_7$) respectively are :

   1. A.four and four
   2. B.five and four
   3. C.five and five
   4. D.four and five
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   Answer: D

2. Q702017 · 8 Apr 2017 · Shift 1

   The pair of compounds having metals in their highest oxidation state is :

   1. A.$\mathrm{M}{\mathrm{n}}_2{\mathrm{O}}_7$ and $\mathrm{Cr}{\mathrm{O}}_2\mathrm{C}{\mathrm{l}}_2$
   2. B.$[\mathrm{NiC}{\mathrm{l}}_4{]}^{2-}$ and $[\mathrm{CoC}{\mathrm{l}}_4{]}^{2-}$
   3. C.$[\mathrm{Fe}(\mathrm{CN}{)}_6{]}^{3-}$ and $[\mathrm{Cu}(\mathrm{CN}{)}_4{]}^{2-}$
   4. D.$[\mathrm{FeC}{\mathrm{l}}_4{]}^{-}$ and $\mathrm{C}{\mathrm{o}}_2{\mathrm{O}}_3$
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   Answer: A

3. Q882017 · 8 Apr 2017 · Shift 1

   In which of the following reactions, hydrogen peroxide acts as an oxidizing agent ?

   1. A.$\mathrm{HOCl}+{\mathrm{H}}_2{\mathrm{O}}_2\to {\mathrm{H}}_3{\mathrm{O}}^{+}+\mathrm{C}{\mathrm{l}}^{-}+{\mathrm{O}}_2$
   2. B.${\mathrm{I}}_2+{\mathrm{H}}_2{\mathrm{O}}_2+2O{\mathrm{H}}^{-}\to 2{\mathrm{I}}^{-}+2{\mathrm{H}}_2\mathrm{O}+{\mathrm{O}}_2$
   3. C.$2\mathrm{Mn}{\mathrm{O}}_4^{-}+3{\mathrm{H}}_2{\mathrm{O}}_2\to 2\mathrm{Mn}{\mathrm{O}}_2+3{\mathrm{O}}_2+2{\mathrm{H}}_2\mathrm{O}+2\mathrm{O}{\mathrm{H}}^{-}$
   4. D.$\mathrm{PbS}+4{\mathrm{H}}_2{\mathrm{O}}_2\to \mathrm{PbS}{\mathrm{O}}_4+4{\mathrm{H}}_2\mathrm{O}$
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   Answer: D