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Outline the tests using aqueous sodium hydroxide and ammonia to identify the following cations: (a) aluminum (Al³⁺), (b) ammonium (NH₄⁺), (c) calcium (Ca²⁺), (d) chromium(III) (Cr³⁺), (e) copper(II) (Cu²⁺), (f) iron(III) (Fe³⁺), (g) iron(II) (Fe²⁺), (h) zinc (Zn²⁺).

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Cambridge IGCSE ChemistryExperimental techniques and chemical analysisCore content

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Outline the tests using aqueous sodium hydroxide and ammonia to identify the following cations: (a) aluminum (Al³⁺), (b) ammonium (NH₄⁺), (c) calcium (Ca²⁺), (d) chromium(III) (Cr³⁺), (e) copper(II) (Cu²⁺), (f) iron(III) (Fe³⁺), (g) iron(II) (Fe²⁺), (h) zinc (Zn²⁺)

  • This point belongs to Identification of ions and gases, especially Identification of ions and gases outcomes.
  • You need to be able to outline the tests using aqueous sodium hydroxide and ammonia to identify the following cations: (a) aluminum (Al³⁺), (b) ammonium (NH₄⁺), (c) calcium (Ca²⁺), (d) chromium(III) (Cr³⁺), (e) copper(II) (Cu²⁺), (f) iron(III) (Fe³⁺), (g) iron(II) (Fe²⁺), (h) zinc (Zn²⁺).
  • The key ideas to know are Describe, Identify, and Outline.
  • Use the linked flashcards and practice questions to check recall, then practise applying the idea in an exam-style answer.

Key concepts

DescribeIdentifyOutline

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Paper 3 structured question: Identification of ions and gases

Paper 3Theory (Core)1 marks

Description

Cation Identification Tests

You are provided with solutions containing various cations. You need to identify them using sodium hydroxide and ammonia.

  1. a

    State the observation when NaOH is added to a solution containing copper(II) ions (Cu²⁺).

    Aim for approximately 1 distinct marking point.

    [1]
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