Tag: d and f block elements

Quizzes (3) Questions (62)

Questions Related to d and f block elements

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Which of the following is not correct?

  1. ${\text{TiC}}{{\text{l}} _{\text{4}}}$ is a colourless compound.
  2. $\left[ {{\text{Cr}}{{\left( {{\text{N}}{{\text{H}} _{\text{3}}}} \right)} _{\text{6}}}} \right]{\text{C}}{{\text{L}} _{\text{3}}}$ is a coloured compound
  3. ${{\text{K}} _{\text{3}}}\left[ {{\text{V}}{{\text{F}} _{\text{6}}}} \right]$ is a colourless compound
  4. $\;\left[ {{\text{Cu}}{{\left( {{\text{NCC}}{{\text{H}} _{\text{3}}}} \right)} _{\text{4}}}} \right]\left[ {{\text{B}}{{\text{F}} _{\text{4}}}} \right]$ is a colourless compound
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Vanadium in K3[VF6] is in the +3 oxidation state with a d2 configuration and undergoes d-d transitions, making it colored. However, the statement claims it is a colourless compound, which is incorrect since many V(III) complexes show color. Therefore, option C describes the false statement.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

The colour imparted by $Co(II)$ compounds to glass is 

  1. green

  2. deep blue

  3. yellow

  4. red
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
 Vanadium yellow-green 
 Chrome emerald green 
 Iron Coke bottle green 
 Manganese amethyst 
 Cobalt violet blue 
 Copper greenish blue to blue 
 Nickel grayish brown 
 Selenium salmon pink 
 Cerium- Titanium yellow 
 Neodymium dichroic violet-pink 
 Uranium yellow (fluorescent 
Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Which of the ions will give colorless aqueous solution?

  1. ${Ni}^{2+}$
  2. ${Fe}^{2+}$
  3. ${Cu}^{2+}$
  4. ${Cu}^{+}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

${Ni}^{2+}$ is light green, ${Fe}^{2+}$ is pale green, 


${Cu}^{2+}$ is blue and ${Cu}^{1+}$ is colorless in aqueous solution as its outermost configuration is $3d^{10}$ so thei is no unpaired electron which causes colour.

Hence ,option D is correct.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

The color of the transition metal ions is due to:

  1. $d-d$ transition

  2. charge transfer

  3. change in the geometry

  4. none
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

In case of transition elements, where the d-level is not completely filled, it is possible to promote an electron from a lower energy d-orbital to a higher energy d-orbital by absorption of a photon of electromagnetic radiation having an appropriate energy. Electromagnetic radiations in the visible region of the spectrum often possess the appropriate energy for such transitions. 

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Which of the following statements are correct with reference to the ferrous and ferric ions?

  1. ${Fe}^{3+}$ gives brown color with potassium ferricyanide
  2. ${Fe}^{2+}$ gives blue precipitate with potassium ferricyanide
  3. ${Fe}^{3+}$ gives red color with potassium thiocyanate
  4. ${Fe}^{2+}$ gives brown color with ammonium thiocyanate
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

Which one of the following ionic species will not impart color to an aqueous solution?

  1. ${Ti}^{4+}$
  2. ${Cu}^{+}$
  3. ${Zn}^{2+}$
  4. ${Cr}^{3+}$
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation
The transition metal ions which have completely filled d-orbitals are colorless.

The transition metal ions which have completely empty d-orbitals are also colorless.

$ Cr^{3+}$ has a blue-green color.  because contain unpair electrons.

Rest all are colorless. 
Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

The colorless species is:

  1. $V{Cl} _{3}$
  2. $VO{SO} _{4}$
  3. ${Na} _{3}{VO} _{4}$
  4. $\left[ V{ \left( { H } _{ 2 }O \right) } _{ 6 }{ SO } _{ 4 } \right] .{ H } _{ 2 }O$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$ VCl _3$ is green.

 
$ VOSO _4$ is blue. 

$ Na _3VO _4$ is colorless vanadium is present in +5 oxidation state .it does not have any unpaired electron.
 
$\left[ V{ \left( { H } _{ 2 }O \right)  } _{ 6 }{ SO } _{ 4 } \right]$ .${ H } _{ 2 }O$ is purple.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

The aqueous solution of the salt will colored in the case of:

  1. $Zn{({NO} _{3})} _{2}$
  2. $Li{NO} _{3}$
  3. $Co{({NO} _{3})} _{2}$
  4. $Cr{Cl} _{3}$
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation

$ Co^{2+}$ = $3d^7$  


$Cr^{3+}$ = $3d^3$
 
$ Co^{2+}$ and $Cr^{3+}$   will have unpaired electrons and hence are expected to have aqueous solution of the salt colored.

Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

What is/are true statement?

  1. Ions of $d$-block elements are colored due to $d-d$ transition
  2. Ions of $f$-block elements are colored due to $f-f$ transtition
  3. ${ \left[ Sc{ \left( { H } _{ 2 }O \right) } _{ 6 } \right] }^{ 3+ },{ \left[ Ti{ \left( { H } _{ 2 }O \right) } _{ 6 } \right] }^{ 4+ }$ are colored complexes.
  4. ${Cu}^{+}$ is colorless ion.
Reveal answer Fill a bubble to check yourself
A,B,D Correct answer
Explanation
$Cu^+$ is colourless because it doesn't contain any electrons which can absorb light. .

In ${ \left[ Sc{ \left( { H } _{ 2 }O \right)  } _{ 6 } \right]  }^{ 3+ }$, $ Sc^{3+}$  is $ d^0$ system and hence colorless.

Hence,option C is incorrect.
Multiple choice chemistry d and f block elements coloured complexes magnetic nature of transition metals general characteristics of first transition series

The aqueous solutions of the following salts will be colored in the case of:

  1. $Zn{({NO} _{3})} _{2}$
  2. $Li{NO} _{3}$
  3. $Co{({NO} _{3})} _{2}$
  4. $Cr{Cl} _{3}$

  5. Potash alum
Reveal answer Fill a bubble to check yourself
C,D Correct answer
Explanation
${Co}^{2+}$
$\uparrow \downarrow $ $\uparrow \downarrow $ $\uparrow $ $\uparrow $ $\uparrow $
$z=27$
$Co=[Ar]{3d}^{7}{4s}^{2}$
${Co}^{2+}=[Ar]{3d}^{7}$
Two unpaired electrons present.

${Cr}^{3+}$:
$z=24$
$Cr=[Ar]{3d}^{5}{4s}^{1}$
${Cr}^{3+}=[Ar]{3d}^{3}$
$\uparrow $ $\uparrow $ $\uparrow $
$Co{({NO} _{3})} _{2}$ and $Cr{Cl} _{2}$ have unpaired electron; hence, they are colored.

The compounds have $ Zn^{2+}, Li^+, Co^{2+} and Cr^{3+}$ with 0, 0, 2 and 3 unpaired electrons. Hence option C and D are correct. Potash alum is colorless.