Neco 2025 Chemistry Question 2

Practice practical question 2 from the 2025 Neco Chemistry examination. This question covers Periodic Table, Qualitative analysis of cations, Precipitation reactions .

Neco 2025 Chemistry Practical
Topics: Periodic Table Qualitative analysis of cations Precipitation reactions
Question 2 NECO • 2025 • CHEMISTRY • practical

A student carries out a systematic qualitative analysis of an unknown aqueous metal salt solution. The following observations are recorded during the test sequence: 1. Addition of dilute HCl produces no visible change. 2. Addition of NaOH results in a blue precipitate which dissolves on adding excess NaOH. 3. Addition of a mixture of NH₄Cl and NH₄OH does not cause the precipitate to re‑appear. 4. Addition of potassium ferrocyanide solution gives a reddish‑brown precipitate. Based on the observations, answer the questions below:

Question Parts

( a )
Identify the metal cation present in the unknown solution and state its group (period and family) in the periodic table.
( b )
Write the balanced chemical equation for the reaction of the identified cation with NaOH that forms the blue precipitate.
( c )
Write the balanced chemical equation for the reaction of the identified cation with potassium ferrocyanide that yields the reddish‑brown precipitate.
( d )
Suggest one source of error that could lead to an incorrect identification of the cation.

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About This Question

This is Neco 2025 Chemistry Question 2. It is one of the practical questions from the 2025 Neco Chemistry examination.

The question covers Periodic Table, Qualitative analysis of cations, Precipitation reactions .

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