ConceptConceptDocsDocuments

Edexcel IAL Chemistry 17.24 ligand exchange and colour changes

Track which ligand replaces water: ammonia can form deep-blue copper ammine complexes, while chloride forms yellow or blue chloro complexes depending on the metal.

Syllabus
First assessment 2019
Course
Chemistry YCH11
Level
A2

Exam points

  • Write ligand exchange equations for copper, cobalt or platinum complex ions.
  • Identify deep-blue tetraamminecopper(II) and yellow tetrachlorocuprate(II) species.
  • Describe colour changes as water ligands are replaced by NH3, Cl- or other ligands.

17.24—Ligand exchange, and an accompanying colour change, occurs in the formation of: i [Cu(NH3)4(H2O)2]2+ from [Cu(H2O)6]2+ via question 1

[Maximum number: 2]

This question is about copper and some of its compounds.

Two tests were carried out on separate samples of an aqueous solution of copper(II) sulfate.

Test 2

A few drops of concentrated hydrochloric acid were added to another sample of the copper(II) sulfate solution.
More of the concentrated hydrochloric acid was added until it was present in excess.

Describe the changes that would be observed during this test.

All question bank results loaded