Class 12 Coordination Compounds worksheet

Sample questions

Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.

Section A · multiple choice

1. 1.

   The number of donor atoms bound to the central metal is its:

   1. atomic number
   2. denticity
   3. oxidation state
   4. coordination number

   Answer

   (d) coordination number

2. 2.

   The oxidation state of Fe in K₂[Fe(en)(NO₂)₄] is:

   1. +2
   2. +3
   3. +1
   4. +4

   Answer

   (a) +2

   the oxidation state plus the ligand charges equals the charge on the complex ion

3. 3.

   The coordination number of Cu in [Cu(H₂O)₄]Cl₂ is:

   1. 6
   2. 2
   3. 3
   4. 4

   Answer

   (d) 4

   count the donor atoms

Section B · short answer

1. 4.

   What is the difference between a double salt and a complex compound?

   Answer

   A double salt such as Mohr's salt dissociates completely into simple ions in water. A complex compound keeps its complex ion intact in water, e.g. K₄[Fe(CN)₆] gives [Fe(CN)₆]⁴⁻ and no Fe²⁺.

2. 5.

   For [Cu(H₂O)₂Cl₂], give the oxidation state and coordination number of the metal, and write its IUPAC name.

   Answer

   +2; 4; diaquadichloridocopper(II)

   oxidation state = charge of complex − sum of ligand charges

Section C · long answer

1. 6.

   Explain the bonding, shape and magnetic behaviour of [Co(NH₃)₆]³⁺ using valence bond theory.

   Answer

   Co³⁺ is 3d⁶. NH₃ makes the six 3d electrons pair in three orbitals, leaving two 3d orbitals empty. These, with 4s and three 4p orbitals, form d²sp³ hybrids that accept six NH₃ lone pairs. The complex is octahedral, inner-orbital and diamagnetic.

Fresh sheets for your child

In the app, every Coordination Compounds sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.

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