Which one of the following reactions involves disproportionation?

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 Multiple Choice QuestionsMultiple Choice Questions

21.

In the disproportionation reaction,

3HClO3 → HClO+ Cl+ 2O+ H2O

the equivalent mass of the oxidising agent is (molar mass of HClO3 = 84.45)

  • 16.89

  • 32.22

  • 84.45

  • 28.15


22.

A compound in which a metal ion Mx+ (Z = 25) has a spin only magnetic moment of 24 BM. The number of unpaired electrons in the compound and the oxidation state of the metal ion are respectively

  • 4 and 2

  • 5 and 3

  • 3 and 2

  • 4 and 3


23.

To an aqueous solution containing anions a few drops of acidified KMnO4 are added. Which one of the following anions, if present will not decolourise the KMnO4 solution ?

  • I-

  • CO32-

  • S2-

  • NO2-


24.

In the following reaction,

Mx+ + MnO4- → MO3- + Mn2+12O2

If one mole of MnO4- oxidises 2.5 moles of Mx+, then the value of x is

  • 5

  • 3

  • 2

  • 1


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25.

MnO-4  ions are reduced in acidic condition to Mn2+ ions whereas they are reduced in neutral condition to MnO2. The oxidation of 25 mL of a solution X containing Fe2+ ions required in acidic condition 20 mL of a solution Y containing MnO-4 ions. What volume of solution Y would be required to oxidise 25 mL of a solution X containing Fe2+ ions in neutral condition? 

  • 11.4 mL

  • 12.0 mL

  • 33.3 mL

  • 35.0 mL


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26.

Which one of the following reactions involves disproportionation?

  • 2H2SO4 + Cu → CuSO4 + 2H2O + SO2

  • As2O3 + 3H2S → As2S3 + 3H2O

  • 2KOH + Cl2 → KCl KOCl + H2O

  • 4NH3 + 3O2 → 2N2 + 6H2O


C.

2KOH + Cl2 → KCl KOCl + H2O

The reactions, in which the same element is oxidised as well as reduced, are called disproportionation reactions.

                    

In this reaction, the same element, ie, Cl2 is oxidised as well as reduced, so it is an example of disproportionation reaction.


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27.

aK2Cr2O7bHCl + cH2SO4 → xCrO2Cl2yKHSO4zH2O.

The above equation balances when:

  • a = 2; b = 4; c = 6 and x = 2; y = 6; z = 3

  • a = 4; b = 2; c = 6 and x = 6; y = 2; z = 3

  • a = 6; b = 4; c = 2 and x = 6; y = 3; z = 2

  • a = 1; b = 4; c = 6 and x = 2; y = 6; z = 3


28.

In one of the following reactions HNO3 does not behave as an oxidizing agent. Identify it :

  • 2HNO3 + P2O5 → 2HPO3 + N2O5

  • I2 + 10 HNO3 → 2HIO3 + 10 NO2 + 4H2O

  • 3Cu + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O

  • NO3 + 3Fe2+ + 4H+ → NO + 3Fe3+ + 2H2O


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29.

In which of the following reactions, H2O2 acts as a reducing reagent?

  • PbO2(s) + H2O(aq) → PbO(s) + H2O(l) +  O2(g)

  • Na2SO3(aq) + H2O2(aq) → Na2SO4(aq) + H2O(l)

  • 2KI(aq) + H2O2(aq) → 2KOH(aq) + I2(s)

  • KNO2(aq) + H2O2(aq) → KNO3(aq) + H2O(l)


30.

In organic reactions, sodium in liquid ammonia is used as

  • reducing agent

  • hydrating agent

  • oxidising agent

  • precipitating agent


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