MnO42- undergoes disproportionation reaction in acidic medium but MnO4- does not?

  • Due to the highest oxidation state of Mn in MnO42-

  •  Due to the highest oxidation state of Mn in MnO4-

  • Due to the endothermic nature of disproportionation reaction

  •  Due to the exothermic nature of disproportionation reaction

Nitric acid reacts with PbO but does not react with PbO, because -

  • PbO is a base while PbO2 is a strong oxidizing reagent

  •  PbO is a base while PbO2 is a weak oxidizing reagent

  •  PbO is neutral while PbO2 is a strong oxidizing reagent

  •  PbO is acid while PbO2 is a strong oxidizing reagent

The oxidation state of P in HPO32- is-

  • +3

  • +4

  • +2

  • +5

the oxidation state of P in PO43-?

  • +2

  • +3

  • +4

  • +5

The oxidation state of two S-atoms in Na2S2O3 is -

  • +2 and +4

  • +3 and -2

  • +4 and -2

  • +6 and -2

(a) EK+/K o= -2.93 V ; EAg+/Ago= 0.80 V

(b) EHg+2/Hgo= 0.79V;  EMg+2/Mgo= -2.37V 

(c) ECr+3/Cro=-0.74 V

Based on standard electrode potentials given above, what is the correct arrangement for increasing order of reducing power of elements? 

  •  Ag < Hg < Cr < Mg < K

  • Ag > Cr > Mg > Hg > K

  • K > Mg <  Cr < Hg > Ag

  • K< Mg < Cr < Hg < Ag

The compound AgF2 (unstable) acts as a/ an:

  • Oxidising agent.

  • Reducing agent.

  • Both oxidising and reducing agent.

  • Neither oxidising and reducing agent.

Among the following hydrohalic compounds, the best reductant is -

1. HCl2. HBr3. HI4. HF

  • 1
  • 2
  • 3
  • 4

The incorrect oxidation number of the underlined atom in the following species

Identify the incorrect option.

  • Cu2O is -1

  • ClO3- is +5

  • K2Cr2O7 is +6

  • HAuCl4  is +3

Identify the reaction from having the top position in the EMF series (standard reduction potential) according to their electrode potential at 298 K.

  • Mg2++ 2eMg(s)

  • Fe2+ + 2e Fe(s)
  • Au3++ 3eAu(s)
  • K++ le K(s)

Standard reduction potentials of the half reactions are given below : 

F2(g) + 2e-2F-(aq) ; E° =+2.85 V 

Cl2(g) + 2e-2Cl-(aq) ; E° =+1.36 V 

Br2(g) + 2e-2Br-(aq) ; E° =+1.06 V 

I2(g) + e-2I-(aq) ; E° =+0.53 V 

The strongest oxidizing and reducing agents, respectively, are: 

  •   Br2 and Cl-

  •   Cl2 and Br-

  •   Cl2 and I2

  •  F2 and l-

A solution contains Fe2+, Fe3+ and I ions. This solution was treated with iodine at 35°C. E° for Fe3+/Fe2+ is +0.77 V and E° for I2/2I = 0.536 V.
The favourable redox reaction is-

  • Fe2+ will be oxidized to Fe3+

  • I2 will be the reduced to I

  • There will be no redox reaction

  • I will be oxidized to I2

The compound that contains zero oxidation state of Fe :

  •  [Fe (CN )6]-4

  •  [Fe (CN )6]-3

  •  Fe (CO )5

  • All of the above .

a Zn + b NO3- + cH+  d NH4+  + e H2O +f Zn+2   ; a , b, c, d, e and f respectively are : 

  • 1
  • 2
  • 3
  • 4

Which is the best description of the behavior of bromine in the reaction given below:-

H2O+Br2HOBr+HBr

  • Both oxidized and reduced

  • Oxidized only

  • Reduced only

  • Proton acceptor only

Oxidation numbers of A, B and C are + 2, +5 and –2 respectively possible formula of compound is :

  • A2(BC2)2

  • A3(BC4)2

  • A2(BC3)2

  • A3(B2C)2

A non feasible reaction among the following is : -

  •  2 KI+Br22KBr+I2

  •  2 KBr+I22KI+Br2

  •  2 KBr+Cl22KCl+Br2

  •  2H2O+2F24HF+O2

Standard electrode potentials are

Fe+2/Fe  E° = -0.44 

 Fe+3/Fe+2  E° = 0.77

If Fe+2 , Fe+3 and Fe  block are kept together, then :- 

  •  Fe+3 increases 

  •  Fe+3 decreases 

  •  Fe+2Fe+3 remains unchanged 

  •  Fe+2 decreases

The oxidation states(O.S.) of sulphur in the anions SO32-, S2O42- and S2O62- follow the order -

  •  S2O42-<SO32-<S2O62-

  •  SO32-<S2O42-<S2O62-

  •  S2O42-<S2O62-<SO32-

  •  S2O62-<S2O42-<SO32-

Fluorine reacts with ice as per the following reaction

H2O(s) + F2(g) → HF(g) + HOF(g)

This reaction is a redox reaction because-

  • F2 is getting oxidized.

  • F2 is getting reduced.

  • Both (1) and (2) 

  • None of the above.

The oxidation number of sulphur and nitrogen in H2SO5 and NO3- are respectively-

  • -6,-6

  • +8, +6

  • +6, +5

  • -8, -6

What will be the formulas for the following compounds

(a) Mercury(II) chloride  and (b) Thallium(I) sulphate

  • HgCl2,  Tl2SO4

  • Hg2Cl2, Tl2SO4

  • HgCl2,  TlSO4

  • HgCl2,  Tl3SO4

Consider the following reactions:

(a) 6 CO2(g) + 6H2O(l) C6H12O6(aq) + 6O2(g)

(b) O3(g) + H2O2(l) H2O(l) + 2O2(g)

It is more appropriate to write these reactions as following because:

(a) 6CO2(g) + 12H2O(l) C6H12O6(aq) + 6H2O(l) + 6O2(g)

(b) O3(g) + H2O2(l) H2O(l) + O2(g) + O2(g)

  • Water molecules are also the product of photosynthesis

  • Water molecules are not a product of photosynthesis.

  • Oxygen molecules are also the product of photosynthesis.

  • Oxygen molecules are not a product of photosynthesis.

In the manufacture of benzoic acid from toluene, we use alcoholic potassium permanganate as an oxidant because -

  • The cost of adding an acid or a base can be reduced.

  • The reactions can proceed at a faster rate.

  • Both '1' and '2'

  • Neither '1' nor '2'

Consider the following reactions :

2 S2O32–(aq) + I2(s)  S4O62–(aq) + 2I(aq)

S2O32–(aq) + 2Br2(l) + 5H2O(l)  2SO42–(aq) + 4Br(aq) + 10H+(aq)

The same reductant, thiosulphate react differently with iodine and bromine because-

  • Br2 is a stronger oxidizing agent than I2

  • I2 is a stronger oxidizing agent than Br2

  • Both '1' and '2'

  • Neither '1' nor '2'

The correct statement(s) about the given reaction is -

XeO6aq4-+2F-1aq+6H+aqXeO3(g)+F2(g)+3H2O(l)

  •  XeO64- oxidises F-

  • The oxidation number of F increases from -1  to  zero

  •  XeO64- is a stronger oxidizing agent that F-

  • All of the above.

Consider the following reactions:

Consider the following reactions:

(a) H3PO2(aq) + 4AgNO3(aq) + 2H2O(l) H3PO4(aq) + 4Ag(s) + 4HNO3(aq)

(b) H3PO2(aq) + 2CuSO4(aq) + 2H2O(l) H3PO4(aq) + 2Cu(s) + H2SO4(aq)

c C6H5CHO(l) + 2AgNH32+(aq) + 3OH-(aq)C6H5COO-(aq) + Ag(s) + 4NH3(aq) +H2O(l)(d) C6H5CHO(l) + 2Cu2+(aq) + 5OH-(aq)No change observed

Draw the inference about the behaviour of Ag+ and Cu2+ ions from these reactions 

  • Ag+ is a stronger oxidizing agent than Cu2+

  • Cu2+ is a stronger oxidizing agent than Ag+

  • Ag+ and Cu2+ are reducing agents

  •   Ag+ is a reducing agent and Cu2+ is an oxidising agent

The oxidising agent and reducing agent in the given reaction are

5P4s+12H2Ol+12HO-aq8PH3g+12HPO2-aq

  • Oxidising agent = P4; Reducing agent = P4

  •  Oxidising agent = P4; Reducing agent = H2O

  •  Oxidising agent = H2O; Reducing agent = P4

  • None of the above

The correct statement about the given reaction is-

(CN)2(g) + 2OH-(aq) CN-(aq) + CNO-(aq) + H2O(l)

  • The reaction is an example of a disproportionation reaction

  • Hydrogen atom gets oxidized

  • Reaction occurs in acidic medium

  • None of the above

The Mn3+ ion is unstable in solution and undergoes disproportionation reaction to give Mn2+, MnO2 and H+ ion. The balanced ionic equation for the reaction is-

 

  • 2Mn3+(aq) + 2H2O(l) → MnO2(s) + Mn2+(aq) + 4H+(aq)

  • Mn3+(aq) + H2O(l) → MnO2(s) + 2Mn2+(aq) + 4H+(aq)

  • 5Mn3+(aq) + 2H2O(l) → MnO2(s) + 3Mn2+(aq) + 4H+(aq)

  • 2Mn3+(aq) + 2H2O(l) → 2MnO2(s) + 2Mn2+(aq) + 4H+(aq)

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