Experiment 10 - Identification of Unknown Metal Ions

What is the identity of the white precipitate formed in test tube E?

• Barium chloride, BaCl₂

• Silver chloride, AgCl

• Copper(II) chloride, CuCl₂

What happen when 2 drops of H₂SO₄ is added to test tube A?

• White precipitate is formed.

• The solution remain colourless.

• Greyish-blue solution is formed.

What is the purpose of heating the test tubes in a water bath after the ethanol test?

• To expel the ethanol

• To warm the mixture for next reaction

• To dissolve the precipitate formed in the test tubes.

The formation of dark blue solution after the addition of ammonia solution in test tube C indicates the presence of ____ ions.

• Ag⁺

• Fe³⁺

• Cu²⁺

Name the equipment in the picture.

• Water bath

• Centrifuge machine

• Hotplate

• Weighing balance

Which of the following is not the correct way of using centrifuge machine?

• Close the lid after placing the samples.

• Place the centrifuge tubes at adjacent side.

• Open the lid only after the rotar had stopped completely.

The _____ in centrifuge tube B and D are discarded into the sink.

• supernatant

• precipitate

• suspension

Identify the role of H₂O₂ in this experiment.

• Act as a strong reducing agent

• Act as an strong oxidising agent

• Act as an precipitating agent

The metal ion presence in test tube D is ______ .

• Cu²⁺

• Fe³⁺

• Cr³⁺

Which of the following unknown solution containing Cr³⁺ ions?

• Unknown solution A

• Unknown solution B

• Unknown solution C

• Unknown solution D

• Unknown solution E