Isomerism - Structural and Stereoisomerism - UNSOLVED PRACTICE SET

Q7. What is linkage isomerism? Give one example involving the ambidentate ligand NO₂⁻.

Q8. Distinguish between geometrical and optical isomerism. Which one is also called cis-trans isomerism?

Q9. The complex [Co(NH₃)₅SO₄]Br and [Co(NH₃)₅Br]SO₄ are isomers. What type of isomerism do they exhibit? Explain.

Q10. Why does [Co(en)₃]³⁺ show optical isomerism while [Co(NH₃)₆]³⁺ does not? Explain.

Q11. Draw the structures of cis and trans isomers of [Pt(NH₃)₂Cl₂]. Which one is used in cancer therapy?

Q12. What is hydrate isomerism? Illustrate with an example from the chromium(III) chloride hydrates.

Q13. Explain the different types of structural isomerism exhibited by coordination compounds. Give one example for each type.

Q14. (a) What is stereoisomerism? Name and explain the two types of stereoisomerism found in coordination compounds.

(b) Which of the following complexes will exhibit geometrical isomerism? Draw the isomers where applicable:

(i) [Co(NH₃)₅Cl]²⁺

(ii) [Co(en)₂Cl₂]⁺

(iii) [Pt(NH₃)₂Cl₂]

(iv) [Ni(CO)₄]

Q15. (a) Explain why [Co(en)₃]³⁺ exhibits optical isomerism. Draw the structures of the two optical isomers.

(b) Will the complex [Co(en)₂Cl₂]⁺ show optical isomerism? If yes, draw all possible isomers (both geometrical and optical). If no, explain why.

Q16. A coordination compound with the formula CoCl₃·4NH₃ has two isomeric forms:

Isomer A: Violet colour, gives 1 mole of AgCl precipitate per mole with AgNO₃

Isomer B: Green colour, gives 1 mole of AgCl precipitate per mole with AgNO₃

(a) Write the structural formulae of both isomers.

(b) Name the type of isomerism exhibited.

(c) Draw the structures of both isomers.

(d) Explain why both give the same amount of AgCl precipitate.

(e) A third isomer C is known which gives 2 moles of AgCl. Write its formula and name the type of isomerism between A and C.

Q17. Consider the following pairs of complexes. Identify the type of isomerism in each pair and explain:

(a) [Co(NH₃)₆][Cr(CN)₆] and [Cr(NH₃)₆][Co(CN)₆]

(b) [Co(NH₃)₅Cl]SO₄ and [Co(NH₃)₅SO₄]Cl

(c) [Cr(H₂O)₆]Cl₃ and [Cr(H₂O)₅Cl]Cl₂·H₂O

(d) [Co(NH₃)₅(NO₂)]²⁺ and [Co(NH₃)₅(ONO)]²⁺

(e) [Pt(NH₃)₂Cl₂] (cis) and [Pt(NH₃)₂Cl₂] (trans)

Q18. In a school science exhibition, a student displays models of coordination compounds to demonstrate isomerism. She shows three models:

Model 1: Two identical ligands are adjacent to each other (90° apart)

Model 2: Two identical ligands are opposite each other (180° apart)

Model 3: A complex that is non-superimposable on its mirror image

(a) What type of isomerism is demonstrated by Models 1 and 2? Name these models using appropriate prefixes.

(b) The student uses [Co(en)₂Cl₂]⁺ to demonstrate Models 1 and 2. Draw the structures of both forms. Does either form show optical isomerism? Explain.

(c) What type of isomerism is demonstrated by Model 3? Give an example of a complex that shows this.

(d) The student explains that cis-[Pt(NH₃)₂Cl₂] is used as an anti-cancer drug while the trans form is inactive. What does this tell you about the importance of isomerism in biological systems?