Qualitative Analysis

What gas will be tested by placing a glowing wooden splinter into a test tube?

• Nitrogen

• Hydrogen

• Oxygen

• Carbon dioxide

How to test sulphur dioxide gas?

• Use damp blue litmus paper

• Test with acidified potassium manganate (VII) solution

• Use damp red litmus paper

• Test with glass rod dipped into concentrated ammonia solution

Copper (II) nitrate salt, Cu(NO₃)₂ is heated with high heat in a boiling tube. State the observations on the colour of residue and the gases released

(a)  

The following results are obtained in a laboratory activity to investigate the effect of heat on a sample of salt Y.

Colourless gas turns limewater cloudy

the colour of residue is yellow when it is hot and white when it is cooled

Identify salt Y.

(a)  

A green solid X was dissolved in water. The observation dissolves in water to produce green solution. What could be in solid X? (Multiple answer)

• Chromium (III) chloride

• Nickel (II) chloride

• Copper (II) chloride

• Iron (II) chloride

When an aqueous solution of a salt Q was tested with alkali solutions, the following observations was obtained.

A white precipitate that is insoluble in an excess of sodium hydroxide solution NaOH.

No change on the addition of ammonia solution, NH₃ to the salt solution.

What cation may be present in the salt?

(a)  

Which of the following ion could give an insoluble white precipitate in excess sodium hydroxide solution, NaOH?

• Magnesium ion, Mg²⁺

• Aluminium ion, Al³⁺

• Lead (II) ion, Pb²⁺

• Zinc ion, Zn²⁺

Both aluminium ion and lead (II) ion give same observation when tested with ammonia solution, NH₃ and sodium hydroxide solution, NaOH. Which reagent / solution can be used to confirm the ions present?

• Nessler reagent

• Potassium hexacyanoferate (II) solution

• Potassium hexacyanoferate (III) solution

• Potassium iodide solution

Nessler reagent is used to confirm the present of ammonium ion, NH4⁺. What is the observation obtained when this reagent is tested with the ammonium contained solution?

• Brown precipitate formed

• Dark blue precipitated formed

• Colourless solution formed

• Yellow precipitate formed

An anion test is carried out as follows for solution M:

Add nitric acid solution, HNO₃ followed by silver nitrate, AgNO₃. A white precipitate formed.

What anion is present in solution M?

• Nitrate ion, NO₃^-

• Chloride ion, Cl^-

• Bromide ion, Br^-

• Sulphate ion, SO₄^2-