The yellow colour solution of Na2CrO4 changes to orange-red on passing CO2 gas due to the formation of :

(1) CrO5                                         

(2) CrO3

(3) Na2Cr2O7                                 

(4) Cr2O3

Subtopic:  Chemistry of Mn and Cr Compounds |
 79%
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FeCr2O4+4Na2CO3+O2FusionX   H2O   H+YH2O2H+Z

Which of the following statements is true for the compounds [X], [Y] and [Z] ?

1. In all three compounds, the chromium is in +6 oxidation states.
2. [Z] is a deep blue-violet coloured compound which decomposes rapidly in aqueous solution into Cr3+and dioxygen.
3. Saturated solution of [Y] gives a bright orange compound, chromic anhydride, with concentrated H2SO4.
4. All of these
Subtopic:  Chemistry of Mn and Cr Compounds |
 79%
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KMnO4 on treatment with conc. H2SO4 forms a compound (X) which decomposes explosively on heating forming (Y). The (X) and (Y) are respectively :

(A) Mn2O7, MnO2                                       

(B) Mn2O7, Mn2O3

(C) MnSO4, MnO2                                       

(D) Mn2O3-, MnO42-

Subtopic:  Chemistry of Mn and Cr Compounds |
 57%
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Which of the following products are formed when potassium bromide reacts with potassium permanganate in alkaline pH?

1. BrO3, MnO2                                     

2. BrO4, Mn2+

3. Br2, MnO2                                         

4. Br2O, MnO42

Subtopic:  Chemistry of Mn and Cr Compounds |
 56%
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Assertion : The number of unpaired electrons in the following gaseous ions:

                   Mn3+, Cr3+, V3+ and Ti3+ are 4, 3, 2 and 1 respectively

Reason : Cr3+ is stable in aqueous solution.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
  3. If the assertion is true but the reason is false
  4. If both the assertion and reason are false
Subtopic:  d-Block Elements- Properties & Uses |
 69%
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Assertion : Cuprous ion Cu+ is colourless whereas cupric ion Cu2+ produces blue colour in solution.

Reason : Cuprous ion Cu+ has unpaired electrons while cupric ion Cu2+ does not.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
  3. If the assertion is true but the reason is false
  4. If both the assertion and reason are false
Subtopic:  d-Block Elements- Properties & Uses |
 71%
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Assertion : Ammonical silver nitrate converts glucose to gluconic acid and metallic silver is precipitated.

Reason : Glucose acts as a weak reducing agent.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
  3. If the assertion is true but the reason is false
  4. If both the assertion and reason are false
Subtopic:  d-Block Elements- Properties & Uses |
 62%
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Assertion: To a solution of potassium chromate if a strong acid is added it changes its colour from yellow to orange.

Reason : The colour change is due to the oxidation of potassium chromate.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
  3. If the assertion is true but the reason is false
  4. If both the assertion and reason are false
Subtopic:  Chemistry of Mn and Cr Compounds |
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Which one of the following statements is not correct

1. Nickel forms Ni(CO)4

2. All the transition metals form mono-metallic carbonyls

3. Carbonyl are formed by transition metals

4. Transition metals form complexes

Subtopic:  d-Block Elements- Properties & Uses |
 87%
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Which of the following pairs of compounds are more stable

(A) K2[NiCl6],[Pt(CN)4]2-

(B) NiCl4, PtCl4

(C) [Ni(CN)4]2-, K2[Pt(Cl6)]

(D) PtCl2, NiCl2

Subtopic:  d-Block Elements- Properties & Uses |
 69%
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