What do you understand by the stability constant, K s of a complex. Knowing that the value of K s for Cu NH 3 4 2 + is 4 . 5 × 10 11 and for Cu CN 4 2 - is 2 . 0 × 10 27 . Suggest (a) which complex species will furnish less Cu 2 + ions in the solution. (b) which out of NH 3 and CN - is a stronger base?

A stability constant which is also called formation constant is an equilibrium constant for the formation of a coordination complex in a solution. It is a measure of the strength of the interaction between the reagents that come together to form the complex in a chemical reaction. For the reaction: M + 3 L ⇌ ML 3 , Stability constant K s = ML 3 M L 3 (a) Stability constant for Cu NH 3 4 2 + is given as: K s = Cu NH 3 4 2 + Cu 2 + aq NH 3 aq 4 = 4 . 5 × 10 11 Stability constant for Cu CN 4 2 - is given as: K s = Cu CN 4 2 - Cu 2 + aq CN - aq 4 = 2 . 0 × 10 27 Clearly, the concentration of Cu 2 + furnished by Cu CN 4 2 - is less compared to that furnished by Cu NH 3 4 2 + complex ion. (b). As CN - ligand formed more stable coordination complex with Cu 2 + compared to NH 3 ligand, thus, CN - ligand is a stronger base than NH 3 .

What is a bidentate ligand? Give one example.

When a ligand has two donor atoms which may simultaneously coordinate to the metal atom are known as didentate or bidentate ligands. Didentate ligands are also called chelating ligands. Examples of didentate ligands include ethane-1,2-diammine, oxalate ion, glycinate ion, etc.

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NEW SYSTEMATIC MODERN CHEMISTRY>Chapter 9 - Coordination Compounds>REVIEW EXERCISES>Q 2

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12th West Bengal Board

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What is meant by unidentate, didentate and ambidentate ligands? Give two examples for each.

Important Questions on Coordination Compounds

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12th West Bengal Board

IMPORTANT

NEW SYSTEMATIC MODERN CHEMISTRY>Chapter 9 - Coordination Compounds>REVIEW EXERCISES>Q 3

Write the main postulates of Werner's coordination theory and explain the bonding in coordination compounds with the help of Werner's postulates. What is the main weakness of Werner's theory.