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Class 12 Chemistry Chapter 9 Ncert Solutions in English 

Class 12 Chemistry NCERT Solutions: Adda247 provides NCERT Solutions for Class 12 Chemistry Chapter 9. The NCERT Solutions provided here will enhance the concepts of the students, as well as suggest alternative methods to solve particular problems to the teachers.

Chemistry is much more than the language of Science. We aim to aid the students with answering the questions correctly using a logical approach and methodology. The NCERT Solutions provide ample material to enable students to form a good base with the fundamentals of the subject.

Students who are looking for Class 12 Chemistry NCERT Solutions can refer to this article. Students will be provided detailed Class 12 Chemistry Chapter 9 NCERT Solutions. Students can find here NCERT Solutions of Class 12 Chemistry PDF in Hindi and English medium.

Students of Class 12 must be through with Science NCERT Class 12 Chemistry Solutions in order to secure good marks in the board exams. These solutions will not only help the students to prepare for board exams but also prepare for competitive medical and engineering entrance exams.

Benefits of Solutions of NCERT Solutions Class 12 Chemistry Chapter 9:

  • NCERT Solutions for Class 12 is helpful to solve questions from other reference books too.
  • NCERT Solutions for Class 12 Chemistry will assist students to cross-check answers and prepare for the exams in a strategic way.

The students can access the solutions anywhere while browsing the web easily. The solutions are very precise and accurate.

NCERT solution for Class 12 Chemistry Chapter – 9 Coordination Compounds.

The process of organizing people or groups so that they work together properly and well.

Coordination Compounds include such substances as vitamin B12, hemoglobin and chlorophyll, dyes and pigments, and catalysts used in preparing organic substances.

Coordination compounds contain a central metal atom surrounded by nonmetal atoms or groups of atoms, called ligands.

Importance of Coordination Compounds;

Coordination Compounds are a major feature of the chemistry of over half the elements.

Coordination compounds have important roles as industrial catalyst in controlling reactivity, and they are essential in biochemical processes.

Coordination compounds generally display a variety of distinctive physical and chemical properties, such as color, magnetic susceptibility, solubility and volatility, and ability to undergo oxidation-reduction reactions, and catalytic activity.

NCERT Solutions for Class 12 Chemistry Chapter 9 help students learn about “coordination compounds” and understand the concepts related to them. However, this chapter which is included in the class 12 chemistry syllabus is an important concept as we talk about atoms and chemical reactions. Chapter 9 explains different compounds formed from transition metals. The unique properties of these compounds are discussed in this chapter. Some of the topics that you will study here are the naming of coordination compounds in the IUPAC system and finding the corresponding chemical formulae when an IUPAC name is given. Chapter 9 also discusses essential terms like ligands, central atom, and coordination entity along with coordination number.


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Key features of NCERT solutions for Class 12 Chemistry Chapter 9: Coordination Compounds

  • These solutions are in clear and easy language.
  • Columns are used wherever necessary.
  • Using these solutions, students will be able to address their doubts and conceptual mistakes.

Working out on more and more problems will help students to perform well in class 12 Board exams. NCERT Solution gives the answer to all these exercise in a clear, simple and straightforward way. Students can check their answers with the solutions provided. It is also another way coordination compounds class 12 NCERT solutions help students.


Important questions of NCERT Solutions Class 12 Chemistry Chapter 9

Question: 1 Explain the bonding in coordination compounds in terms of Werner’s postulates.


Following are the postulates of Werner’s theory:

  • In coordination compound metals shows two types of linkages – primary and secondary.
  • The primary valances are normally ionisable and are satisfied by negative ions.
  • The secondary valances are non-ionisable. These are satisfied by neutral molecules or negative ions. The secondary valances is equal to the coordination no. and is fixed for a metal.
  • The ions/groups bound by the secondary linkages to the metal have characteristics spatial arrangements corresponding to different coordination numbers.


Question: 2 FeSO4 solution mixed with (NH4)2SO4 solution in 1 : 1 molar ratio gives the test of Fe2+ ion but CuSO4 solution mixed with aqueous ammonia in 1 : 4 molar ratio does not give the test of Cu2+ ion. Explain why?


FeSO4 does not form any complex with (NH4(SO4). Instead, they form a double salt, FeSO4.(NH4)2SO4.6H2O (Mohr salt) which dissociates completed in ion in the solution. Hence, it gives the test of Fe2+ ions. CuSO4 solution mixed with aqueous ammonia in 1 : 4 molar ratio forms the complex with the formula [Cu(NH3)]SO4 in which the complex ion, [Cu(NH3)4]2+ does not dissociate to give Cu2+ ions. Hence, it does not give the tests of Cu2+ ion.


Question: 3 Explain with two examples each of the following: coordination entity, ligand, coordination number, coordination polyhedron, homoleptic and heteroleptic.


  • Coordination entity: Coordination entity constitutes a central metal atom or ion bounded to a fixed no. of ions or molecules.

For example, [CoCl3(NH3)3], [Ni(CO)4].



  • Ligand: The ions or molecules bound to the central atom/ion in the coordination entity are called ligands.

For example, H2o, NH3.


  • Coordination number: The coordination number of a metal ion in complex can be defined as the no. of ligand donor atom to which the metal is directly bonded.

For example, In PtCl6]2-, the coordination no. of Pt is 6. In [Ni(NH3)4]2+, the coordination no. of Ni is 4.


  • Coordination polyhedron: The spatial arrangement of the ligand atoms which are directly attached to the central atom/ion defines a coordination polyhedron about the central atom.

For example, [PtCl4]2- is square planar, [Ni(CO)4] is tetrahedral.


  • Homoleptic complexes: Complexes in which a metal is bound to only one kind of donor group are known as homoleptic complexes.

For example, [Co(NH3)6]3+


  • Heteroleptic complexes: Compleses in which a metal is bound to more than one kind of donor groups are known as heteroleptic complexes.

For example, [Co(NH3)4Cl2]+.


Question: 4 What is meant by unidentate, didentate and ambidentate ligands? Give two examples of each.


  • Unidentate ligands: When a ligand is bound to a metal ion through a single donor atom, the ligand is known as unidentate ligand.

For example, Cl, H2O.

  • Didentate ligand: When a ligand can be bind through two donor atoms, the ligand is said to be didentate ligand.

For example, (ethane-1,2-diamine), (oxalate).

  • Ambidentate ligand: Ligand which can ligate through two different atoms is called ambidentate ligand.

For example, NO2, SCN.


Question: 5 Specify the oxidation numbers of the metals in the following coordination entities:

  • [Co(H2O)(CN)(en)2]2+
  • [CoBr2(en)2]+
  • [PtCl4]2-
  • K3[Fe(CN)6]
  • [Cr(NH3)3Cl3]


Let x be the oxidation no. of metal in the following compounds;

  • X + 0 + (-1) + 2(0) = +2

X – 1 = 2

X = 1

  • X + 2(-1) +2(0) = +1

X – 2 = 1

X = 3

  • X + 4(-1) = -2

X – 4 = -2

X = +2

  • 3(+1) + x + 6(-1) = 0

3 + x + (-6) = 0

X = 3

  • X + 3(0) + 3(-1) = 0

X + (-3) = 0

X = 3


Question:6 Using IUPAC norms write the formula of following:

  • Tetrahydroxozincate(II)
  • Potassium tetrachloridopalladate(II)
  • Pottasium tetracynanickelate(II)
  • Diamminedichloridoplatinum(II)
  • PENTAamminenitrito- O- cobalt(III)
  • Hexaamminecobalt(III) sulphate
  • Potassium tri(oxalate)chromate(III)
  • Hexaammineplatinum(IV)
  • Tetrabromidocuprate(II)
  • Pentaamminenitrito-N-cobalt(III)


  • [Zn(OH)4]2-
  • K2[PdCl4]
  • [Pt(NH3)2Cl2]
  • K2[Ni(CN)4]
  • [Co(ONO)(NH3)5]2+
  • [Co(NH3)6]2(SO4)3
  • K3[Cr(C2O4)3]
  • [Pt(NH3)6]4+
  • [Cu(Br)4]2-
  • [Co(NO2)(NH3)5]2+


Question:7 Using IUPAC norms write the systematic names of the following:

  • [Co(NH3)6]Cl3
  • [Pt(NH3)2Cl(NH2CH3)]Cl
  • [Ti(H2O)6]3+
  • [CO(NH3)4Cl(NO2)]Cl
  • [Mn(H2O)6]2+
  • [NiCl4]2-
  • [Ni(NH3)6]Cl2
  • [CO(en)3]3+
  • [Ni(CO)4]


  • Hexaamminecobalt(III) chloride


(ii)          Diamminechlorido(methylamine) platinum(II) chloride


  • Hexaquatitanium(III) ion


(iv)        Tetraamminichloridonitrito-N-Cobalt(III) chloride


(v)           Hexaquamanganese(II) ion


(vi)          Tetrachloridonickelate(II) ion


(vii)         Hexaamminenickel(II) chloride


(viii)        Tris(ethane-1, 2-diammine) cobalt(III) ion


(ix)         Tetracarbonylnickel(0)


Question: 8 Give the oxidation state, d orbital occupation and coordination no. of the central metal ion in the following complexes:

  • K3[Co(C2O4)3]
  • (NH4)2[CoF4]
  • cis-[Cr(en)2Cl2]Cl
  • [Mn(H2O)6]SO4


  • K3[Co(C2O4)3]

The central metal ion is Co

Its coordination no. is 6


The oxidation state of Co is

X – 6 = -3x = +3

The d orbital occupation for Co3+ is t2g6eg0


  • (NH4)2[CoF4]

The central metal ion is Co

The coordination no. is 4

The oxidation state of Co is

X – 4 = -2

X = +2

The d orbital occupation for Co2+ is eg4t2g3


  • cis-[Cr(en)2Cl2]Cl

the central metal ion is Cr

its coordination no. is 6

The oxidation state of Cr

X + 2(0) + 2(-1) = 1

X = +3

The d orbital occupation for Cr3+ is t2g3


  • [Mn(H2O)6]SO4

The central metal ion is Mn

Its coordination no is 6

The oxidation state of Mn

X + 2 = 0

X = 2

The d orbital occupation for Mn2+ is t2g3eg2



Question: 9 Write down the IUPAC name for each of the following complexes and indicate the oxidation state, electronic configuration and coordination number. Also give stereochemistry and magnetic moment of the complex:

  • K[Cr(H2O)2(C2O4)2].3H2O
  • [Co(NH3)5Cl]Cl2
  • CrCl3(py)3
  • Cs[FeCl4]
  • K4[Mn(CN)6]


Compound IUPAC name Oxidation state Electronic configuration Coordination number Stereochemistry Magnetic moment


Potassium diaquabisoxalatochromate (III)trihydrate +3 [Ar]3d3 6 Cis and trans 3.87


Pentaminechorocobaltate(III)chloride +3 [Ar]3d6 6 No stereoisomerism 4.90


Trichlorotripyridine chromate(III) +3 [Ar]3d3 6 Fac. And mar. isomers 3.87


Caseium tetrachloroferrate(III) +3 [Ar]3d5 4 No 5.92


Potassium hexacynomanganate(II) +2 [Ar]3d5 6 no 5.92



Question: 10 What is meant by stability of a coordination compound in solution? State the factors which govern stability of complexes.


The stability of coordination compounds in solution means the degree of association between the metal ion and the ligands involved in the state of equilibrium. Quantitatively, the stability is expressed by the equilibrium constant for the association.

M +3L -à ML3

Stability Constant, = [ML]/[M][L3]

For this reaction., the greater the value of the stability constant, the greater is the proportion of ML3 in the solution.

FAQs Based on Class 12 Chemistry Chapter 9 Ncert Solutions

  1. How to prepare for the Coordination Compounds Chapter?

Ans. To prepare for coordination compound chapter, you must require the use of class 12 Chemistry chapter 9 exercise solutions. Some other tips to help you prepare for coordination compounds.

Study the chapter at least three times. Then practice more and more problems given in the exercise. If they are not so easy to solve, you can consult the chapter 9 chemistry class 12 NCERT Solutions from online study resources. After that you should practice the previous year question papers and sample papers.

This much preparation is all it takes for students to prepare for the coordination compounds chapter.


  1. How important is the Coordination Compounds Chapter?

Ans. The coordination compounds chapter is a fairly important chapter in the inorganic section of Class 12 chemistry. Coordination compounds form an essential topic along with d and f block elements. The inorganic chemistry carries 12 marks. The Coordination compounds class 12 NCERT solutions will help students to understand their work better. This chapter is very essential for the inorganic section of the chemistry question paper. Students can download coordination compounds class 12 NCERT solutions for better result.


  1. How to solve the Coordination compounds Questions?

Ans. Chemistry chapter 9 will primarily have questions related to the naming of the Chemical formula of the compounds. Drawing the orbitals is very important for different compounds. Then students may be asked to explain why certain compounds have certain colors. If you are looking for the solutions to these problems, it is worth downloading coordination compounds class 12 NCERT solutions. This will help you write precise answers to all the NCERT problems. Also, those students who are able to solve the questions should try to check their work using coordination compounds class 12 NCERT solutions PDF.


  1. What can I learn from Chapter 9 of NCERT Solutions for Class 12 Chemistry?

Ans. From Chapter 9 of NCERT Solutions for Class 12 Chemistry, you can learn about topics/subtopics like-

  • Werner’s Theory of Coordination Compounds.
  • Definition of Some Important Terms Pertaining to Coordination compounds.
  • Nomenclature of Coordination compounds.
  • Isomerism in Coordination Compounds.
  • Bonding in Coordination Compounds.
  • Bonding in Metal Carbonyls.
  • Stability of Coordination Compounds.
  • Importance and applications of Coordination Compounds.


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