Question 12 Marks
Identify coordination sphere and counter ions.
Answer
View full question & answer→Coordination sphere : $[Ni(NH_3)_6]^{2+}$
Counter ions : $CI^–$
Counter ions : $CI^–$
Questions
Answer the following in one or two sentence.
Take a timed test
16 questions · self-marked practice — reveal the answer and mark yourself.
Question 22 Marks
A complex is made of $Co$ (III) and consists of four $NH_3$ molecules and two $CI^–$ ions as ligands. What is the charge number and formula of complexion?
Answer
View full question & answer→The complex ion has formula,$[Co(NH_3)_4CI_2]^+.$
The charge number is $+ 1.$
The charge number is $+ 1.$
Question 32 Marks
Can you write ionisation of $[Ni (NH_3)_6] CI_2?$
Answer
View full question & answer→$[Ni (NH_3)_6] CI_2 \rightarrow [Ni(NH_3)_6]^{2+} + 2CI^–$
Question 42 Marks
Mention two applications of coordination compounds.
Answer
View full question & answer→(1) In biology: Several biologically important natural compounds are metal complexes which play an important role in number of processes occurring in plants and animals. For example, chlorophyll in plants is a complex of $Mg ^{2+}$ ions, haemoglobin in blood is a complex of iron, vitamin $B _{12}$ is a complex of cobalt.
(2) In medicine: The complexes are used on a large scale in medicine. Many medicines in the complex form are more stable, more effective and can be assimilated easily.
For example, platinum complex $\left[ Pt \left( NH _3\right)_2 Cl _2\right]$ known as cisplatin is effectively used in cancer treatment. EDTA is used to treat poisoning by heavy metals like lead.
(3) To estimate hardness of water :
(4) Electroplating: This involves deposition of a metal on the other metal. For smooth plating, it is necessary to supply continuously the metal ions in small amounts.
For this purpose, a solution of a coordination compound is used which dissociates to a very less extent. For example, for uniform and thin plating of silver and gold, the complexes $K \left[ Ag ( CN )_2\right]$ and $K \left[ Au ( CN )_2\right]$ are used.
(2) In medicine: The complexes are used on a large scale in medicine. Many medicines in the complex form are more stable, more effective and can be assimilated easily.
For example, platinum complex $\left[ Pt \left( NH _3\right)_2 Cl _2\right]$ known as cisplatin is effectively used in cancer treatment. EDTA is used to treat poisoning by heavy metals like lead.
(3) To estimate hardness of water :
- The hardness of water is due to the presence $Mg ^{2+}$ and $Ca ^{2+}$ ion in water.
- The strong field ligand EDTA forms stable complexes with $Mg ^{2+}$ and $Ca ^{2+}$. Hence these ions can be removed by adding EDTA to hard water.
(4) Electroplating: This involves deposition of a metal on the other metal. For smooth plating, it is necessary to supply continuously the metal ions in small amounts.
For this purpose, a solution of a coordination compound is used which dissociates to a very less extent. For example, for uniform and thin plating of silver and gold, the complexes $K \left[ Ag ( CN )_2\right]$ and $K \left[ Au ( CN )_2\right]$ are used.
Question 52 Marks
Consider the complexes $[Cu(NH_3)_4][PtCl_4]$ and $[Pt(NH_3)_4] [CuCl_4]$. What type of isomerism these two complexes exhibit?
Answer
View full question & answer→Since in these two given complexes, there is an exchange of ligands between cationic and anionic constituents, they exhibit coordination isomerism.
Question 62 Marks
Is the complex $[CoF_6]$ cationic or anionic if the oxidation state of cobalt ion is $+3$?
Answer
View full question & answer→In the complex, Co carries $+ 3$ charge while $6F^–$ carry $– 6$ charge. Hence the net charge on the complex is$ – 3$.
Therefore it is an anionic complex.
Therefore it is an anionic complex.
Question 72 Marks
What is the shape of a complex in which the coordination number of central metal ion is 4?
Answer
View full question & answer→A complex with the coordination number of central metal ion equal to 4 may be tetrahedral or square planar.
Question 82 Marks
Name the Lewis acids and bases in the complex $[PtCl_2(NH_3)_2].$
Answer
View full question & answer→Lewis acid : $Pt^{2+}$
Lewis bases : $Cl^–$ and $NF_3$
Lewis bases : $Cl^–$ and $NF_3$
Question 92 Marks
Predict whether the $[Cr(en)_2(H_2O)_2]^{3+}$ complex is chiral. Write structure of its enantiomer.
Answer
View full question & answer→(i) Complex is chiral.
(ii) The following are its enantiomers
(ii) The following are its enantiomers
Question 102 Marks
Write the formula for tetraammineplatinum (II) chloride.
Answer
View full question & answer→Formula of tetraamineplatinum(II) chloride : $[Pt(NH_3)_4]CI_2$
Question 112 Marks
An octahedral complex absorbs the radiation of wavelength 620 nm. Find the crystal field splitting energy.
Answer
View full question & answer→Crystal field splitting energy $\Delta_0$ is given by,
$\begin{aligned}
& \Delta_0=\Delta E=\frac{h C}{\lambda}=\frac{6.63 \times 10^{-34} \times 3 \times 10^8}{620 \times 10^{-9}} \\
& m \quad \\
&=3.2 \times 10^{-19} J
\end{aligned}$
$\begin{aligned}
& \Delta_0=\Delta E=\frac{h C}{\lambda}=\frac{6.63 \times 10^{-34} \times 3 \times 10^8}{620 \times 10^{-9}} \\
& m \quad \\
&=3.2 \times 10^{-19} J
\end{aligned}$
Question 122 Marks
Explain the factors affecting Crystal Field Splitting parameter $\left(\Delta_0\right)$.
Answer
View full question & answer→Crystal Field Splitting parameter $\left(\Delta_0\right)$ depends on. (a) Strength of the ligands and (b) Oxidation state of the metal.
(a) Strength of the ligands : Since strong field ligands like $CN ^{-}$, en, etc. approach closer to the central metal ion, it results in a large crystal field splitting and hence $\Delta_0$ has higher values.
(b) Oxidation state of the metal A metal ion with the higher positive charge draws the ligands closer to it which results in large separation of $t _{2 g }$ and $e _{ g }$ set of orbitals. The complexes involving metal ions with low oxidation state have low values of $\Delta_0$. For example $\left[ Fe \left( NH _3\right)_6\right]^{3+}$ has higher $\Delta_0$ than $\left[ Fe \left( NH _3\right)_6\right]^{2+} \cdot H$
(a) Strength of the ligands : Since strong field ligands like $CN ^{-}$, en, etc. approach closer to the central metal ion, it results in a large crystal field splitting and hence $\Delta_0$ has higher values.
(b) Oxidation state of the metal A metal ion with the higher positive charge draws the ligands closer to it which results in large separation of $t _{2 g }$ and $e _{ g }$ set of orbitals. The complexes involving metal ions with low oxidation state have low values of $\Delta_0$. For example $\left[ Fe \left( NH _3\right)_6\right]^{3+}$ has higher $\Delta_0$ than $\left[ Fe \left( NH _3\right)_6\right]^{2+} \cdot H$
Question 132 Marks
What is crystal field stabilisation energy?
Answer
View full question & answer→Crystal field stabilisation energy (CFSE) It is the change in energy achieved by preferential filling up of the orbitals by electrons in the complex of metal atom or ion.
CFSE is expressed as a negative .quantity i.e., $C F S E \leq 0$. Higher the negative value more is the stability of the complex. $m$
CFSE is expressed as a negative .quantity i.e., $C F S E \leq 0$. Higher the negative value more is the stability of the complex. $m$
Question 142 Marks
What is crystal field splitting?
Answer
View full question & answer→The splitting of five degenerate d-orbitals of the transition metal ion into different sets of orbitals $\left( to _{2 g }\right.$ and $e _{ g }$ ) having different energies in the presence of ligands in the complex is called crystal field splitting.
Question 152 Marks
A coordination compound has the formula $COCl _3 6 H _2 O$. Write the hydrate isomers of the complex.
Answer
View full question & answer→The possible hydrate isomers of the coordination compounds having molecular formula $COCl _3$ $6 H _2 O$ are as follows :
(1) $\left[ CO \left( H _2 O \right)_6\right] Cl _3$;
(2) $\left[ CO \left( H _2 O \right)_5 Cl \right] Cl _2 H _2 O$
(3) $\left[ CO \left( H _2 O \right)_4 Cl _2\right] Cl -2 H _2 O$
(4) $\left[ Co \left( H _2 O \right)_3 Cl _3\right] 3 H _2 O$.
(1) $\left[ CO \left( H _2 O \right)_6\right] Cl _3$;
(2) $\left[ CO \left( H _2 O \right)_5 Cl \right] Cl _2 H _2 O$
(3) $\left[ CO \left( H _2 O \right)_4 Cl _2\right] Cl -2 H _2 O$
(4) $\left[ Co \left( H _2 O \right)_3 Cl _3\right] 3 H _2 O$.
Question 162 Marks
Define solvate or hydrate isomers.
###
What are hydrate isomers? Explain with examples.
###
What are hydrate isomers? Explain with examples.
Answer
View full question & answer→Solvate or Hydrate isomers : The coordination compounds having the same molecular formula but differ in the number of solvent or $H _2 O$ molecules inside the coordination sphere and outer sphere of the complexes are called solvate or hydrate isomers.
For example : $\left[ Cr \left( H _2 O \right)_6\right] Cl _3 ;\left[ Cr \left( H _2 O \right)_5 Cl \right] Cl _2 H _2 O$; and $\left[ Cr \left( H _2 O \right)_4 Cl _2\right] Cl 2 H _2 O$.
For example : $\left[ Cr \left( H _2 O \right)_6\right] Cl _3 ;\left[ Cr \left( H _2 O \right)_5 Cl \right] Cl _2 H _2 O$; and $\left[ Cr \left( H _2 O \right)_4 Cl _2\right] Cl 2 H _2 O$.