Equilibria chemistry
 

Ligand exchange equilibria

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Self assessment

Question 1 of 5

When concentrated hydrochloric acid is added to aqueous copper(II) sulfate, the complex [CuCl4]2– is formed. The colour of the solution changes from blue through green to yellow. What is the likely cause of the green colour?

A

A mixture of [Cu(H2O)6]2– ions and [CuCl4]2– ions.

B

[Cu(H2O)6]2+ ions.

C

[CuCl4]2– ions.

D

[Cu(H2O)6Cl4]2– ions.

What type(s) of bonding are found in the compound [Cu(H2O)6]2+SO42–?

A

Covalent bonding.

B

Dative covalent bonding.

C

Metallic bonding.

D

Ionic bonding.

Which of the following is a polydentate ligand?

A

Water.

B

Ammonia.

C

Chloride ion.

D

edta

What is the correct expression for Kstab of the [Cu(NH3)4(H2O)2]2+ ion?

A

The expression for Kstab is \inline \dpi{100} \mathit{K =}\frac{[\textup{Cu(NH}_{3})_{4}(\textup{H}_{2}\textup{O})_{2}^{2+}][\textup{H}_{2}\textup{O}]^{4}}{[\textup{Cu}(\textup{H}_{2}\textup{O}{})_{6}^{2+}][\textup{NH}_{3}]^{4}}

B

The expression for Kstab is \inline \dpi{100} \mathit{K =}\frac{[\textup{Cu(NH}_{3})_{4}(\textup{H}_{2}\textup{O})_{2}^{2+}]}{[\textup{Cu(H}_{2}\textup{O})_{6}^{2+}][\textup{NH}_{3}]^{4}}

C

The expression for Kstab is \inline \dpi{100} \mathit{K =}\frac{[\textup{Cu(NH}_{3})_{4}(\textup{H}_{2}\textup{O})_{2}^{2+}]}{[\textup{Cu(H}_{2}\textup{O})_{6}^{2+}]}

D

The expression for Kstab is \inline \dpi{100} \mathit{K = }\frac{[\textup{Cu(H}_{2}\textup{O})_{6}^{2+}][\textup{NH}_{3}]^{4}}{[\textup{Cu(NH}_{3})_{4}(\textup{H}_{2}\textup{O})_{2}^{2+}]}

The lg Kstab value for [Cu(en)(H2O)4]2+ is 10.6. The lg Kstab value of [Cu(edta)]2– is 18.8. What does this mean?

A

 [Cu(en)(H2O)4]2+ is more stable than [Cu(edta)]2–.

B

[Cu(edta)]2– is more stable than [Cu(en)(H2O)4]2+.

C

[Cu(en)(H2O)4]2+ is more stable than [Cu(H2O)6]2+.

D

[Cu(edta)]2– is more stable than [Cu(H2O)6]2+.
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