Colours in Coordination Compounds

Q.

What is spectrum

What are it's types

Q. The coordination complex, $\left[Cu\right(O{H}_2{)}_6{]}^{2+}$ has one unpaired electron. Which of the following statements are true about the coordination complex, $\left[Cu\right(O{H}_2{)}_6{]}^{2+}$ ?
(1) The complex is octahedral.
(2) The complex is an outer orbital complex.
(3) The complex is $d^{2}d{p}^3$ hybridized.
(4) The complex is diamagnetic.
(5) The coordination number is $6$.

1. $1,4$
2. $1,2,5$
3. $2,3,5$
4. $2,3$

Q. The colour of light absorbed by an aqueous solution of $CuS{O}_4$ is:

1. Orange – red
2. Blue – green
3. Yellow
4. Violet

Q.

What is the colour of Ferric chloride?

Q. The coordination number of a central metal atom in a complex(s) is/are not determined by

1. The number of only anionic ligands bonded to the metal ion
2. The number of ligands around a metal ion bonded by $\pi -$bonds
3. The number of ligands around a metal ion bonded by both $\sigma \text{and}\pi$bonds
4. The number of ligands around a metal ion bonded by $\sigma$ bonds

Q. Brine is an aqueous solution of:

1. Sodium hydroxide
2. Sodium carbonate
3. Sodium chloride
4. Sodium bicarbonate

Q.

Why are different colours observed in octahedral and tetrahedral complexes for the same metal and same ligands?

Q.

What is the colour of Ferrous sulphide?

Q.

Match the complex ions given in Column I with the colours given in Column II and assign the correct code.
$\begin{array}{cc}\text{Column~I}& \text{Column~II}\\ \left(Complexion\right)& \left(Colour\right)\\ A.\left[Co\right(N{H}_3{)}_6{]}^{3+}& 1.Violet\\ B.\left[Ti\right(H_{2}O{)}_6{]}^{3+}& 2.Green\\ C.\left[Ni\right(H_{2}O{)}_6{]}^{2+}& 3.Paleblue\\ D.\left[Ni\right(H_{2}O{)}_4\left(en\right){]}^{2+}\left(aq\right)& 4.Yellowixhorange\end{array}$

Codes

$\begin{array}{ccccc}& A& B& C& D\\ \left(a\right)& 1& 2& 4& 5\\ \left(b\right)& 4& 3& 2& 1\\ \left(c\right)& 3& 2& 4& 1\\ \left(d\right)& 4& 1& 2& 3\end{array}$

Q. The type of hybridization involved in the metal ion of $\left[Ni\right(H_{2}O{)}_6{]}^{2+}$ complex is

1. $d^{3}s{p}^2$
2. $s{p}^3{d}^2$
3. $s{p}^3$
4. $ds{p}^2$

Q.

What is the relationship between observed colour of the complex and the wavelength of light absorbed by the complex?

Q. Crystal field stabilization energy for the complex ion [FeF6]⁴- is: 1)-4Dq 2)-24Dq 3)-16Dq 4)-20Dq

Q. The correct energy level diagram for $\left[Co\right(CN{)}_6{]}^{3-}$ is

1. 
2. 
3. 
4. 

Q. Which among the following will be named as dibromidobis(ethylenediamine)chromium(III) bromide?

1. $\left[Cr\right(en{)}_3]B{r}_3$
2. $\left[Cr\right(en{)}_{2}B{r}_2]Br$
3. $\left[Cr\right(en)B{r}_4{]}^{-}$
4. $\left[Cr\right(en\left)B{r}_2\right]Br$

Q. Which of the following is coordination compound?

1. Ferrous ammonium sulphate
2. Carnallite
3. Potassium ferrocyanide
4. Gypsum

Q. For the given aqueous reactions, which of the statement (s) is (are) true?

1. The first reaction is a redox reaction
2. White precipitate is $Z{n}_3\left[Fe\right(CN{)}_6{]}_2$
3. Addition of filtrate to starch solution gives blue colour
4. White precipitate is soluble in NaOH solution

Q.

$CuS{O}_4.5H_{2}O$ is blue in colour while $CuS{O}_4$ is colourless. Why?

Q. Consider the following transformation ${\left[Co\right(H_{2}O{)}_x]}^{3+}$ (Pink complex) $\stackrel{\text{Excess HCl}}{\to }{\left[CoC{l}_y\right]}^{n-}$ (Blue complex). Find the value of expression $\frac{x+y}{n}$.

Q.

$\left[Fe\right(CN{)}_6{]}^{4-}$ and $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$ are of different colours in dilute solutions. Why?

Q. Two complexes $\left[Cr\right(H_{2}O{)}_6]C{l}_3$ $\left(A\right)$ and
$\left[Cr\right(N{H}_3{)}_6]C{l}_3$ $\left(B\right)$ are violet and yellow coloured, respectively. The incorrect statement regarding them is:

1. ${\Delta }_o$ value of (A) is less than that of (B).
2. ${\Delta }_o$ value of (A) and (B) are calculated from the energies of violet and yellow light, respectively
3. Both absorb energies corresponding to their complementary colors.
4. Both are paramagnetic with three unpaired electrons.

Q. A compound absorbing violet colour from sunlight will be

1. Green
2. orange
3. violet
4. yellow

Q. The correct increasing order of wavelengths of absorption in the visible region for the complexes of $C{o}^{3+}$ is:

1. $\left[Co\right(en{)}_3{]}^{3+},\left[Co\right(N{H}_3{)}_6{]}^{3+},\left[Co\right(H_{2}O{)}_6{]}^{3+}$
2. $\left[Co\right(H_{2}O{)}_6{]}^{3+},\left[Co\right(en{)}_3{]}^{3+},\left[Co\right(N{H}_3{)}_6{]}^{3+}$
3. $\left[Co\right(H_{2}O{)}_6{]}^{3+},\left[Co\right(N{H}_3{)}_6{]}^{3+},\left[Co\right(en{)}_3{]}^{3+}$
4. $\left[Co\right(N{H}_3{)}_6{]}^{3+},\left[Co\right(en{)}_3{]}^{3+},\left[Co\right(H_{2}O{)}_6{]}^{3+}$

Q.

A solution of $\left[Ni\right(H_{2}O{)}_6{]}^{2+}$ is green but a solution of $\left[Ni\right(CN{)}_4{]}^{2-}$ is colourless. Explaiin.

Q. Which of the following is coloured tetrahedral complex species?

1. $\left[Cu\right(PP{h}_3{)}_4{]}^{+}$
2. $\left[Zn\right(H_{2}O{)}_6{]}^{2+}$
3. $\left[Cu\right(N{H}_3{)}_4]S{O}_4$
4. $Mn{O}_4^{-}$

Q. The oxidation state and coordination number of cobalt in the complex $CoC{l}_3.5N{H}_3$ are respectively:

1. 3 and 6
2. 6 and 3
3. 6 and 2
4. 5 and 3

Q. A salt ion gives violet vapours when treated with concentrated sulphuric acid, means salt contains :

1. chloride
2. none of the above
3. bromide
4. iodide

Q. The correct order of wavelengths of absorption is:

1. $\left[Ni\right(N{O}_2{)}_6{]}^{4-}<\left[Ni\right(N{H}_3{)}_6{]}^{2+}<\left[Ni\right(H_{2}O{)}_6{]}^{2+}$
2. $\left[Ni\right(N{O}_2{)}_6{]}^{4-}<\left[Ni\right(H_{2}O{)}_6{]}^{2+}<\left[Ni\right(N{H}_3{)}_6{]}^{2+}$
3. $\left[Ni\right(H_{2}O{)}_6{]}^{2+}<\left[Ni\right(N{H}_3{)}_6{]}^{2+}<\left[Ni\right(N{O}_2{)}_6{]}^{4-}$
4. $\left[Ni\right(N{H}_3{)}_6{]}^{2+}<\left[Ni\right(H_{2}O{)}_6{]}^{2+}<\left[Ni\right(N{O}_2{)}_6{]}^{4-}$

Q. A solution of $\left[Ni\right(H_{2}O{)}_6{]}^{2+}$ is green but a solution of $\left[Ni\right(CN{)}_4{]}^{2-}$ is colourless, Explain.

Q. In the brown ring test, the brown complex formed :

1. has a formal +1 oxidation state on $Fe$
2. has +2 charge on $Fe$
3. shows a magnetic moment of 3.9 BM
4. has the brown colour due to charge transfer from $NO$ to $Fe$

Q. The brown ring complex is formulated as$\left[{Fe\left(H_{2}O\right)}_{5}NO\right]{SO}_4$. The oxidation state of iron is:
(A) +1 (B) +2 (C) +3 (D) 0