GCSE Edexcel Chemistry Nanoparticles: Qualitative tests are used to id

Question

Qualitative tests are used to identify ions.

(a) A student carries out a flame test on an unknown solid.
A red flame is seen.
The student concludes that the solid is lithium carbonate.
Explain why this conclusion is not justified. (2)

(b) The following tests were carried out on a substance containing two ions.
1. A flame test on the solid substance produced a yellow colour.
2. Dilute hydrochloric acid was added to a solution of the substance followed by a few drops of barium chloride solution.
A white precipitate formed.
Give the name and formula of the substance. (2)

Name of substance

Formula of substance

(c) The test for chloride ions was carried out on a solution.
Dilute nitric acid was added to the solution, followed by a few drops of silver nitrate solution.
A white precipitate formed.
Why is it necessary to add dilute nitric acid in this test? (1)

A To neutralise the solution
B Nitrate ions are needed for the test to work

(d) Sodium hydroxide solution is used to identify some cations present in compounds.
(i) Sodium hydroxide solution is warmed with a solution of ammonium ions.
Ammonia gas is given off.
Describe the test to show the gas is ammonia. (2)

(ii) Sodium hydroxide solution is also used to distinguish between iron(II) ions, Fe²⁺ and iron(III) ions, Fe³⁺, in solution.
You are given a solution containing iron(II) ions and another solution containing iron(III) ions.
Describe the test when sodium hydroxide solution is added to each of

Qualitative tests are used to identify ions - Edexcel - GCSE Chemistry - Question 6 - 2016 - Paper 1

Worked Solution & Example Answer:Qualitative tests are used to identify ions - Edexcel - GCSE Chemistry - Question 6 - 2016 - Paper 1

Explain why this conclusion is not justified.

Give the name and formula of the substance.

Why is it necessary to add dilute nitric acid in this test?

Describe the test to show the gas is ammonia.

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