Which one of the following transition metal ion is coloured? fro

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 Multiple Choice QuestionsMultiple Choice Questions

131.

Which of the following two ions have the same number of unpaired electrons ?

(1) Mn3+       (2) Fe3+      (3) Cr3+      (4) Co3+

 

  • (2) and (3)

  • (3) and (4)

  • (1) and (2)

  • (1) and (4)


132.

The lanthanoid contraction is responsible for the fact that

  • Zn and Y have about same radius

  • Zr and Nb have similar oxidation states

  • Zr and Hf have about the same radius

  • Zr and Zn have the same oxidation state


133.

The equivalent weight of MnSO4, is equal to its molecular weight when it is converted to

  • Mn2O3

  • MnO2

  • MnO4-

  • MnO42-


134.

The mineral from which potassium permanganate is manufactured

  • manganite, Mn2O3.H2O

  • pyrolusite, MnO2

  • Both (a) and (b)

  • None of the above


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135.

Which one of the following transition metal ion is coloured?

  • Cu+

  • Zn2+

  • Sc3+

  • V4+


D.

V4+

Among the given options, V4+ is coloured.

The electronic configuration of V4+ is [Ar]3d1 4s0. It has one unpaired electron in its d-subshell. On exposure to visible light, the excitation of unpaired d-electrons takes place from lower to higher energy d-sublevels. The d-d excitation during complex formation permits the  absorbance of required wavelength and rest light is transmitted out. Thus, transition metals or metal ions having unpaired d-electrons appears coloured.


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136.

Correct order of paramagnetism is

  • Mn>Cr> Zn

  • Fe> Zn> Cr

  • Cr> Fe> Zn

  • Zn >Mn> Fe


137.

The aqueous ferrous ion is green, ferric ion is pale yellow. The aqueous chromic ion is green, hence the colour of chromate ion must be

  • orange

  • colourless

  • yellow

  • red


138.

In acidic medium, the equivalent weight of  K2Cr2O7 (Mol. wt. = M) is

  • M

  • M/2

  • M/3

  • M/6


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139.

U92235 belongs to IIIB group of the Periodic.When it loses one α -particle, the new element will belong to the group.

  • I B

  • V B

  • I A

  • III B


140.

Which set of elements have nearly the same atomic radii ?

  • F, Cl, Br, I

  • Na, K, Rb, Cs

  • Fe, Co, Ni, Cu

  • Li, Be, B, C


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