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NCERT Solutions for Class 12 Chemistry Chapter 9 – Coordination Compounds

NCERT Solutions for Class 12 Chemistry Chapter 9 – Coordination Compounds help you prepare for the CBSE Class 12 Board exams. This unit of class 12th syllabus provides knowledge about coordination entity, central atom/ion, ligand, coordination number, coordination sphere, homoleptic and heteroleptic complexes. You will also learn about writing the formulas and names of coordination compounds and different types of isomerism in coordination compounds. You will understand the nature of bonding in coordination compounds in terms of the Valence Bond and Crystal Field theories and also learn about applications of coordination compounds in daily life.

In this chapter, there are a total of 32 questions asked at the end. All of these questions are intended to cover all the concepts taught in NCERT CBSE Class 12 Chemistry Chapter 9. The questions given in this chapter enable you to have a deep insight into the concepts of coordination compounds such as nomenclature of coordination compounds, colour, coordination number, different types of isomerism, spectrochemical series, and uses of coordination compounds.

All of these questions are answered comprehensively in NCERT Solutions for Class 12 Chemistry Chapter 9 – Coordination Compounds. They follow all the guidelines given by CBSE and NCERT. These are precise solutions that help you learn effectively. They are just what you need to ace your Class 12 board exams.

NCERT Class 12 Chemistry Chapter 9: Important Topics

NCERT Solutions for Class 12 Chemistry Chapter 9 – Coordination Compounds incorporates all the concepts of the unit coordination compounds. An outline of the concepts covered in this chapter are as follows –

  • Werner’s Theory of Coordination Compounds

This part of the chapter tells about the postulates of Werner’s theory according to which in a coordination compound, metals show two types of linkages (valences)-primary (ionisable) and secondary (non-unusable). The coordination number is actually the secondary valence. It remains fixed for metal and also shows characteristic arrangements in space corresponding to different coordination numbers.

  • Definitions of Some Important Terms Related to Coordination Compounds

In this portion, you learn about coordination entities which are made up of a central metal atom or ion attached to a definite number of ions or neutral molecules called ligands. A chelate ligand is a di- or polydentate ligand using its two or more donor atoms simultaneously to bind a single metal ion. The number of donor atoms of ligands, to which the metal is directly attached in a coordination compound is known as the coordination number (CN) of the metal ion.

This portion further tells you about the coordination sphere in which the central atom or ion and the ligands linked to it are kept in square brackets. The spatial arrangement of the ligand atoms linked to the metal atom/ion make a polyhedron shape about the central atom and the common coordination polyhedra are tetrahedral, square planar and octahedral.

Further, it tells that in homoleptic complexes, the central atom is bound to only one kind of donor ligand whereas, in heteroleptic complexes, the donor ligands are of more than one type.

  • Nomenclature of Coordination Compounds

This part of the chapter teaches you the rules applied to name a coordination compound which follow the principles of additive nomenclature.

  • Isomerism in Coordination Compounds

This part of the chapter teaches you about two main types of isomerism namely stereoisomerism (having two subdivisions geometrical isomerism and optical isomerism) and structural isomerism (having three subdivisions, linkage isomerism, coordination isomerism, ionisation isomerism and solvate isomerism).

  • Bonding in Coordination Compounds

This part of the chapter tells about the valence bond theory (VBT) according to which the metal atom or ion can use its valence orbitals for hybridisation, when influenced by ligands, to yield a set of equivalent orbitals of a particular geometry. This portion further explains the formation of a coordination compound, its magnetic properties and three-dimensional shape. Still, VBT fails to offer a quantitative interpretation of magnetic behaviour and reason for the optical properties of the coordination compounds.

Further in this chapter crystal field theory (CFT) has been discussed as a purely electrostatic model which assumes that ligands are point charges and they affect the degeneracy of d orbital energies of the central metal atom/ion by splitting the d orbitals into different energy levels. This provides the reason behind the difference in electronic arrangements in strong and weak crystal fields. CFT provides numerical assessments of magnetic moments, orbital separation energies, spectral and stability parameters.

Further, this chapter mentions about spectrochemical series, which is the arrangement of ligands in order of their increasing field strengths and also that colour in the coordination compounds can be readily explained in terms of the crystal field theory.

This portion further discusses the limitations of CFT, where it does not explain the splitting effects of anionic ligands and also does not consider the covalent character of bonding between the ligand and the central atom.

  • Bonding in Metal Carbonyls

This part of the chapter tells you that a lot of transition metals make simple carbonyl compounds. The metal-carbon bond here enjoys having both σ and π bonds. In M-C σ bond, an electron pair is donated by CO to metal, and in M-C π bond it’s the other way. Hence, this becomes a unique synergic bonding system providing stability to metal carbonyls.

  • Importance and Applications of Coordination Compounds

This part of the chapter talks about the importance of coordination compounds. These compounds help in explaining the functioning and structures of important constituents of biological systems. They are extensively applied in metallurgical processes, analytical and medicinal chemistry purposes.

CBSE NCERT Class 12 Chemistry Chapter 9 Exercise

Our NCERT Solutions for Class 12 Chemistry Chapter 9 – Coordination Compounds consists of 30 questions covering the important topics learnt here. The components of the exercise have been listed below. 

  • Questions 1 and 2 are based on Werner’s theory.
  • Question 3 is a direct question based on definitions of terms.
  • Questions 5 to 7, 24 are based on the nomenclature of coordination compounds.
  • Questions 8 to 12 are based on isomerism in coordination compounds.
  • Questions 13, 14, 19, 20. 21 are explanatory questions.
  • Question 15 is based on valence bond theory.
  • Questions 16, 18 are based on crystal field theory.
  • Question 17 is a direct question on spectrochemical series.
  • Question 22 asks you to discuss the bonding in metal carbonyls.
  • Question 25 is a direct question on the stability of coordination compounds.
  • Question 26 is based on the chelate effect.
  • Question 27 is based on the application of coordination compounds.
  • Questions 28 to 32 are multiple-choice questions.

There are 11 intext questions asked in CBSE NCERT Class 12 Chemistry Chapter 9 to which suitable answers are provided in our solutions.

Benefits of NCERT Solutions for Class 12th Chemistry Chapter 9 – Coordination Compounds 

Some of the major benefits of NCERT Solutions for Class 12 Chemistry Chapter 9 – Coordination Compounds are as given below –

  • They are convenient, useful, precise and user-friendly.
  • All the questions have detailed answers. They give you an in-depth and holistic overview of the chapter.
  • They are well-structured, they follow a logical flow and give you enough practice to get used to the kind of questions that can be asked in your board exams.
  • They impart clarity, effectiveness, efficiency and speed to the learning and revision processes required during examinations.

They help you to score high marks in class 12th board exams.