Detection of Cations questions

Dilute HCl acid is used to detect the ions ..........

1. A Ag⁺ , Ca²⁺ , CO₃²⁻
2. B Fe²⁺ , Pb²⁺ , S²⁻
3. C Ag⁺ , Hg⁺ , SO₄²⁻
4. D Pb²⁺ , Hg⁺ , S₂O₃²⁻

A mercury(I) nitrate solution can be distinguished from a potassium nitrite solution using ..........

1. A NaCl
2. B PbCl₂
3. C NH₄NO₃
4. D KNO₃

A clear solution forms when hydrochloric acid is added to the salt ..........

1. A Ag₂CO₃
2. B Pb(CO₃)₂
3. C Hg₂CO₃
4. D CuCO₃

The ion that can be detected using dilute HCl acid is ..........

1. A SO₄²⁻
2. B Fe²⁺
3. C PO₄³⁻
4. D Pb²⁺

We have a solution containing a mixture of the anions SO₄²⁻ , Cl⁻
Which cation, when added to this mixture, precipitates one of these two anions?

1. A Pb²⁺
2. B Ba²⁺
3. C NH₄⁺
4. D Mg²⁺

HCl(aq) is used to detect the cation of the confirmatory reagent of each of the following anions, except ..........

1. A PO₄³⁻
2. B SO₄²⁻
3. C NO₃⁻
4. D I⁻

Which of the following salts are soluble in water?

1. A PbCl₂ : insoluble ; Pb(NO₃)₂ : soluble ; PbS : insoluble
2. B PbCl₂ : insoluble ; Pb(NO₃)₂ : soluble ; PbS : soluble
3. C PbCl₂ : soluble ; Pb(NO₃)₂ : insoluble ; PbS : insoluble
4. D PbCl₂ : soluble ; Pb(NO₃)₂ : insoluble ; PbS : soluble

Dilute hydrochloric acid was added to a solid salt and a gas was given off; passing it into lead(II) acetate solution forms a black precipitate, and when hydrochloric acid is added to the black precipitate it turns into a white precipitate.
The chemical formula of the white precipitate formed is ..........

1. A CaCl₂
2. B PbCl₂
3. C HgCl₂
4. D AgCl

Dilute hydrochloric acid was added to a solution containing the ions Cu²⁺ , Mn²⁺ , Ba²⁺ , Pb²⁺, and precipitate (X) formed. After separating this precipitate, sulphuric acid was added to the remaining solution and precipitate (Y) formed.
Which of the following is correct?

1. A Precipitate (X) : PbCl₂ , precipitate (Y) : BaSO₄
2. B Precipitate (X) : BaCl₂ , precipitate (Y) : PbSO₄
3. C Precipitate (X) : PbCl₂ , precipitate (Y) : MnSO₄
4. D Precipitate (X) : MnCl₂ , precipitate (Y) : CuSO₄

A solution of NaX(aq) reacted with a solution of AgY(aq), forming a solution and a yellow precipitate.
What are the names of the two groups to which the cation and the anion of the precipitate formed belong, respectively?

1. A Analytical group II , dilute H₂SO₄ acid group.
2. B Analytical group I , dilute HCl acid group.
3. C Analytical group V , BaCl₂ solution group.
4. D Analytical group I , conc. H₂SO₄ acid group.

The two ions of the solution of the compound used in purifying drinking water can each be detected separately using ..........

1. A NH₄OH(aq) , HCl(aq)
2. B (NH₄)₂CO₃(aq) , H₂S(g)
3. C CaCl₂(aq) , H₂S(g)
4. D (CH₃COO)₂Pb(aq) , HCl(aq)

All the following salt solutions form a black precipitate when H₂S gas is passed into them, except ..........

1. A AgNO₃
2. B (CH₃COO)₂Pb
3. C Cu(NO₃)₂
4. D NaCl

The precipitates formed when H₂S gas is passed into a solution containing the ions Cu²⁺ , Pb²⁺ , K⁺ are ..........

1. A PbS , CuS
2. B CuS , K₂S
3. C PbS , K₂S
4. D CuS , Pb

Which of the following pairs of cations can be used to separate the sulphide anion?

1. A Ag⁺ , K⁺
2. B Ag⁺ , Cu²⁺
3. C Cu²⁺ , Na⁺
4. D K⁺ , Na⁺

An aqueous solution contains a mixture of the ions Cu²⁺ , Ag⁺
What must be added to this solution to precipitate one of the two ions but not the other?

1. A H₂S(aq)
2. B HCl(aq)
3. C HNO₃(aq)
4. D Na₂CO₃(aq)

When testing for the cation of a salt solution, it was found that it does not form a precipitate with the SO₄²⁻ anion but forms a precipitate with the S²⁻ anion.
What is the symbol of this cation?

1. A Ba²⁺
2. B NH₄⁺
3. C Ca²⁺
4. D Cu²⁺

A fixed amount of CuSO₄(aq) was added separately to three tubes containing equal amounts of BaCl₂(aq) , KCl(aq) , Na₂S(aq). In which of the following cases does a precipitate form?

1. A In the case of Na₂S only.
2. B In the cases of BaCl₂ , Na₂S only.
3. C In the cases of BaCl₂ , KCl only.
4. D A precipitate forms in all cases.

Which of the following gives the suitable experiments for detecting a copper(II) sulphate solution?

1. A Adding HCl acid : right ; adding H₂S in an acidic medium : right ; adding Ba(NO₃)₂ solution : wrong
2. B Adding HCl acid : right ; adding H₂S in an acidic medium : wrong ; adding Ba(NO₃)₂ solution : right
3. C Adding HCl acid : wrong ; adding H₂S in an acidic medium : right ; adding Ba(NO₃)₂ solution : wrong
4. D Adding HCl acid : wrong ; adding H₂S in an acidic medium : right ; adding Ba(NO₃)₂ solution : right

When the following ions are mixed in water:
NO₃⁻ , CO₃²⁻ , Cl⁻ , Cu²⁺ , Ba²⁺ , K⁺ , Pb²⁺ , Ag⁺ , NH₄⁺
the number of compounds that may form as precipitates is ..........

1. A 5
2. B 6
3. C 7
4. D 8

From the following chart:
Which of the following is correct?

1. A Substance (X) : CuO , solution (Y) : Cu(NO₃)₂ , substance (Z) : CuS
2. B Substance (X) : CuS , solution (Y) : Cu(NO₂)₂ , substance (Z) : CuCl₂
3. C Substance (X) : FeO , solution (Y) : Fe(NO₃)₂ , substance (Z) : FeCl₂
4. D Substance (X) : Fe₃O₄ , solution (Y) : Fe(NO₂)₂ , substance (Z) : FeS

The following cations can be separated as precipitates, except ..........

1. A Ag⁺
2. B Na⁺
3. C Fe³⁺
4. D Cu²⁺

When a solution of iron(II) sulphate is exposed to the air for a long enough time, and then sodium hydroxide solution is added to it, ............ takes place.

1. A reduction then precipitation
2. B precipitation then oxidation
3. C oxidation then precipitation
4. D precipitation then reduction

From the following information:
• Cation (X): precipitates as the compound XCl₂
• Cation (Y): precipitates as the compound Y(OH)₂
• Cation (Z): precipitates as the compound ZS
These cations are arranged in ascending order of their analytical groups as follows ..........

1. A X then Y then Z
2. B X then Z then Y
3. C Z then X then Y
4. D Y then X then Z

From the opposite chart:
Which of the following represents each of (X) , (Y)?

1. A (X) : iron(II) chloride , (Y) : iron(II) chloride.
2. B (X) : iron(II) iodide , (Y) : iron(II) chloride.
3. C (X) : iron(III) chloride , (Y) : iron(III) chloride.
4. D (X) : iron(III) iodide , (Y) : iron(III) chloride.

Gas (X):
• its aqueous solution reacts with FeCl₃ solution, forming a reddish-brown precipitate that dissolves in compound (Y).
• it reacts with gas (Z), forming white clouds.
Which of the following is correct?

1. A Gas (X) : NH₃ , compound (Y) : nitric acid , gas (Z) : HCl
2. B Gas (X) : NH₃ , compound (Y) : sodium hydroxide , gas (Z) : NH₄Cl
3. C Gas (X) : SO₃ , compound (Y) : sodium hydroxide , gas (Z) : CO
4. D Gas (X) : SO₃ , compound (Y) : nitric acid , gas (Z) : NH₃

Two identical samples of an unknown salt: hot conc. sulphuric acid was added to the first sample and reddish-brown fumes were given off, and ammonium hydroxide solution was added to the solution of the second sample and a greenish-white precipitate formed.
What is the chemical formula of this salt?

1. A Fe(NO₃)₂
2. B Fe(NO₂)₃
3. C Ca(NO₃)₂
4. D Ca(NO₂)₂

Excess sodium hydroxide solution was added slowly to iron(II) sulphate solution. All the following are correct, except ..........

1. A A greenish-white precipitate forms.
2. B A gas with a pungent smell is given off that turns moist red litmus paper blue.
3. C The colour of the precipitate in the container turns reddish-brown after some time.
4. D The precipitate formed dissolves in hydrochloric acid.

A solid substance (X) is used as a red colour in paints. Which of the following represents the way to detect the cation of substance (X)?

1. A Dissolving substance (X) in water, then adding NH₄OH(aq)
2. B Dissolving substance (X) in water, then adding HNO₃(aq)
3. C Reacting substance (X) with H₂SO₄(aq), then adding (NH₄)₂CO₃(aq)
4. D Reacting substance (X) with hot H₂SO₄(l), then adding KOH(aq)

The following table shows some properties of the compounds Fe(NO₃)₂ , Al(NO₃)₃:
• product of the reaction of Fe(NO₃)₂ with sodium hydroxide solution: (X)
• product of the reaction of Al(NO₃)₃ with sodium hydroxide solution: (Y)
Which of the following is correct?

1. A (X) : greenish-white precipitate , (Y) : white precipitate that dissolves in NH₄OH(aq)
2. B (X) : reddish-brown precipitate , (Y) : black precipitate.
3. C (X) : reddish-brown precipitate , (Y) : white precipitate that turns black on heating.
4. D (X) : greenish-white precipitate , (Y) : white precipitate that does not dissolve in NH₄OH(aq)

An iron(III) chloride solution was divided into three equal samples, then the following was added to sample:
• (1): AgNO₃ solution
• (2): Ba(NO₃)₂ solution
• (3): excess NaOH solution
Which of the following gives the correct observations for the three samples?

1. A (1) : no precipitate forms , (2) : a precipitate forms , (3) : a reddish-brown precipitate forms.
2. B (1) : no precipitate forms , (2) : no precipitate forms , (3) : a precipitate forms then disappears.
3. C (1) : a white precipitate forms , (2) : no precipitate forms , (3) : a reddish-brown precipitate forms.
4. D (1) : a white precipitate forms , (2) : a precipitate forms , (3) : a precipitate forms then disappears.

From the following chart:
The colour of the precipitate formed is ..........

1. A white.
2. B reddish-brown.
3. C greenish-white.
4. D black.

From the following chart:
The cation of the precipitate formed is ..........

1. A Ca²⁺
2. B Al³⁺
3. C Fe²⁺
4. D Fe³⁺

When drops of NaOH solution are added to the products of the reaction of magnetic iron oxide with hot conc. sulphuric acid, ........ forms.

1. A a greenish-white precipitate only
2. B two precipitates, one of which dissolves in dilute HCl acid
3. C a reddish-brown precipitate only
4. D two precipitates, both of which dissolve in dilute HCl acid

When compound (X) is dissolved in distilled water, a solution forms, and when ammonium hydroxide solution is added to the solution of compound (X), a reddish-brown precipitate forms.
Compound (X) is ..............

1. A iron(II) chloride.
2. B iron(II) sulphate.
3. C iron(III) nitrate.
4. D iron(III) hydroxide.

When dilute hydrochloric acid is added to salt (X), solution (Y) and gas (Z) form. When gas (Z) is passed into limewater for a short time a white precipitate forms, and when ammonia solution is added to solution (Y) a greenish-white precipitate forms when exposed to air.
Salt (X) is ..........

1. A iron(II) chloride.
2. B iron(II) carbonate.
3. C calcium carbonate.
4. D calcium chloride.

From the opposite chart:
Which of the following is correct for both compounds (A) , (B)?

1. A Both dissolve in water.
2. B Both react with hydrochloric acid.
3. C Both react with ammonia solution.
4. D Both contain Fe³⁺ cations.

The anion and the cation of a salt can both decolourise acidified potassium permanganate solution.
What is the possible chemical formula of this salt?

1. A Fe(NO₂)₃
2. B Cu(NO₃)₂
3. C Fe(NO₂)₂
4. D Cu(NO₂)₂

A solid substance (X) does not dissolve in water; a gas is given off from it both on strong heating and on reacting with sulphuric acid.
Substance (X) is ..........

1. A iron(III) hydroxide.
2. B iron(II) carbonate.
3. C aluminium hydroxide.
4. D sodium carbonate.

Using the following, where (X , Y , A) are hypothetical symbols for atomic groups or elements:
Which of the following is correct?

1. A (Xᵐ⁻) : sulphite , (Aⁿ⁺) : Fe²⁺
2. B (Xᵐ⁻) : nitrite , (Aⁿ⁺) : Fe³⁺
3. C (Yᵐ⁻) : nitrate , (A⁽ⁿ⁺¹⁾⁺) : Fe³⁺
4. D (Yᵐ⁻) : nitrate , (A⁽ⁿ⁺¹⁾⁺) : Fe²⁺

When potassium hydroxide solution is added to solution (X), a precipitate forms that dissolves in excess KOH(aq), and when barium chloride solution is added to the same solution (X), precipitate (Y) forms.
What is solution (X), and what is the colour of precipitate (Y)?

1. A (X) : CaCl₂ , (Y) : white.
2. B (X) : Al₂(SO₄)₃ , (Y) : white.
3. C (X) : FeCl₂ , (Y) : greenish-white.
4. D (X) : Al₂(SO₄)₃ , (Y) : reddish-brown.

The mixture of iron(II) hydroxide, aluminium hydroxide and iron(III) hydroxide can be turned into a clear solution by adding excess ..........

1. A NaOH(aq)
2. B HCl(aq)
3. C NH₄OH(aq)
4. D H₂O(l)

The following two experiments were carried out on solution (X):
• sodium hydroxide solution was added to a sample of it, and a white precipitate formed that dissolves in excess NaOH
• silver nitrate solution was added to another sample of it, and a white precipitate formed.
From the above observations, we conclude that solution (X) contains the ions ..........

1. A I⁻ , Al³⁺
2. B NO₃⁻ , Fe²⁺
3. C Cl⁻ , Cu²⁺
4. D Cl⁻ , Al³⁺

The two salts lead(II) chloride and aluminium chloride can be distinguished using ..........

1. A water.
2. B nitric acid.
3. C ammonium nitrate solution.
4. D water containing CO₂

Which of the following happens when excess ammonium hydroxide solution is added to aluminium chloride solution?

1. A A white gelatinous precipitate forms and quickly dissolves.
2. B No reaction is observed.
3. C A white gelatinous precipitate forms.
4. D A deep blue solution forms.

Solid substance (X) dissolves in sulphuric acid, forming a colourless solution (Y) and a gas that burns with a pop. When NaOH solution is added to solution (Y), a white precipitate forms that dissolves in excess NaOH(aq), and when barium nitrate solution is added to solution (Y), substance (Z) forms.
What is the name of substance (X), and what are the colour and formula of substance (Z)?

1. A Aluminium , a white precipitate of BaSO₄
2. B Calcium , a white precipitate of Ba(NO₃)₂
3. C Aluminium sulphate , an aqueous solution of BaSO₄
4. D Calcium sulphate , an aqueous solution of BaCl₂

From the opposite Venn diagram:
Which of the following represents each of the properties (1) , (2) , (3)?

1. A (1) : dissolves in HCl acid , (2) : dissolves in NaOH , (3) : changes colour in air
2. B (1) : dissolves in HCl acid , (2) : changes colour in air , (3) : dissolves in NaOH
3. C (1) : changes colour in air , (2) : dissolves in HCl acid , (3) : dissolves in NaOH
4. D (1) : dissolves in NaOH , (2) : dissolves in HCl acid , (3) : changes colour in air

From the following two charts:
The number of compounds that do not dissolve in water is ..........

1. A 2
2. B 3
3. C 4
4. D 5

From the following chart:
Which of the following is used to distinguish between the two solutions (X) , (Y)?

1. A H₂SO₃
2. B Pb(NO₃)₂
3. C CaCl₂
4. D (NH₄)₂SO₄

Which of the following substances reacts with both hydrochloric acid and sodium hydroxide solutions?

1. A NH₄OH
2. B Fe(OH)₃
3. C Fe(OH)₂
4. D Al(OH)₃

If:
• the chloride of cation (X) does not dissolve in water, while the acetate of (X) dissolves in water.
• the chloride of cation (Y) dissolves in water and the hydroxide of (Y) dissolves in NaOH
then all the following are correct, except ..........

1. A The sulphate of (X) dissolves in water.
2. B The sulphate of (Y) dissolves in water.
3. C The charge of cation (X) is less than that of cation (Y).
4. D (X) , (Y) are not in the same analytical group.

7 mol of sodium hydroxide solution were added to 2 mol of aluminium chloride solution.
Which of the following graphs shows the change in the mass of the precipitate formed with time?

1. A Graph (A)
2. B Graph (B)
3. C Graph (C)
4. D Graph (D)

Which graph shows the masses of the precipitates formed when excess NaOH solution is added to three different solutions of the ions Fe²⁺(aq) , Fe³⁺(aq) , Al³⁺(aq), each containing 1 g of its ions?

1. A Graph (A)
2. B Graph (B)
3. C Graph (C)
4. D Graph (D)

Solution (A) contains a mixture of the nitrates of the cations (Fe³⁺ , Ag⁺ , Fe²⁺ , Al³⁺); the experiments shown in the following chart were carried out on it:
Which of the following represents each of the precipitates (B) , (C) and the cations of solution (D)?

1. A Precipitate (B) : FeCl₂ ; precipitates (C) : Fe(OH)₃ , Al(OH)₃ ; cations of solution (D) : Na⁺
2. B Precipitate (B) : FeCl₂ ; precipitates (C) : Fe(OH)₂ , Al(OH)₃ ; cations of solution (D) : Na⁺ , Ag⁺
3. C Precipitate (B) : AgCl ; precipitates (C) : Fe(OH)₂ , Fe(OH)₃ ; cations of solution (D) : Na⁺
4. D Precipitate (B) : AgCl ; precipitates (C) : Fe(OH)₂ , Fe(OH)₃ ; cations of solution (D) : Na⁺ , Al³⁺

An aluminium chloride solution was divided into three test tubes.
Which of the following shows the three suitable reagents for detecting aluminium chloride solution?

1. A First tube : NaOH solution ; second tube : NH₄OH solution ; third tube : dilute HCl acid
2. B First tube : NaOH solution ; second tube : dilute HNO₃ acid and AgNO₃ solution ; third tube : dilute HCl acid
3. C First tube : NH₄OH solution ; second tube : dilute HNO₃ acid and AgNO₃ solution ; third tube : Ba(NO₃)₂ solution
4. D First tube : NaOH solution ; second tube : NH₄OH solution ; third tube : AgNO₃ solution

From the following chart:
Salt (X) is ..........

1. A aluminium chloride.
2. B sodium sulphate.
3. C zinc chloride.
4. D aluminium sulphate.

A series of reactions was carried out on alloy (A), made of two metals, as shown in the following chart:
The two metals that make up alloy (A) are ..........

1. A copper and aluminium.
2. B copper and iron.
3. C iron and aluminium.
4. D zinc and lead.

4 mol of sodium hydroxide solution were added to 1 mol of aluminium sulphate.
Which of the following graphs shows the mass of the precipitate with time?

1. A Graph (A)
2. B Graph (B)
3. C Graph (C)
4. D Graph (D)

0.3 mol of sodium hydroxide solution was added to 0.1 mol of iron(III) hydroxide.
Which of the following represents the mass of iron(III) hydroxide?

1. A Graph (A)
2. B Graph (B)
3. C Graph (C)
4. D Graph (D)

The cations that form a white precipitate with the sulphate anion are ..........

1. A Na⁺ , Ba²⁺
2. B Ca²⁺ , NH₄⁺
3. C Ca²⁺ , Ba²⁺
4. D Al³⁺ , Fe²⁺

All the following pairs of cations can be separated from each other using sodium carbonate solution, except ..........

1. A Hg⁺ , NH₄⁺
2. B Mg²⁺ , K⁺
3. C Na⁺ , Cu²⁺
4. D Ca²⁺ , Pb²⁺

When CaCl₂ solution is mixed with Al₂(SO₄)₃ solution ..........

1. A AlCl₃ precipitates
2. B a CaSO₄ solution forms
3. C CaSO₄ , AlCl₃ precipitate
4. D an AlCl₃ solution forms and CaSO₄ precipitates

Solution (X) reacts with each of the following two solutions separately, forming a white precipitate:
• silver nitrate solution.
• sodium sulphate solution.
What is the possible name of solution (X)?

1. A aluminium chloride.
2. B sodium chloride.
3. C calcium chloride.
4. D iron(III) chloride.

A solution containing Pb²⁺ ions can be distinguished from a solution containing Ca²⁺ ions using ..........

1. A dilute nitric acid.
2. B potassium chloride solution.
3. C sodium sulphate solution.
4. D dilute sulphuric acid.

If hot conc. sulphuric acid is added to salt (X), a white precipitate forms and reddish-brown fumes are given off.
Salt (X) is ..........

1. A calcium carbonate.
2. B calcium nitrate.
3. C iron(II) carbonate.
4. D iron(III) nitrate.

From the following chart:
Which of the following is correct?

1. A Substance (X) : H₂SO₄ , substance (Y) : Ca(OH)₂ , substance (Z) : NaOH
2. B Substance (X) : CaCO₃ , substance (Y) : NaOH , substance (Z) : CaSO₄
3. C Substance (X) : H₂SO₄ , substance (Y) : NaOH , substance (Z) : Ca(OH)₂
4. D Substance (X) : CaSO₄ , substance (Y) : Ca(OH)₂ , substance (Z) : CaCO₃

Ammonium carbonate solution was added to a solution of salt (A), and a white precipitate (B) formed.
What is the effect of adding dilute HCl acid to precipitate (B), and what colour do the cations of salt (A) give in the dry test?

1. A A gas is given off that turns clear limewater milky, and the cation gives a golden yellow colour.
2. B The precipitate dissolves and the non-luminous zone of the Bunsen flame turns brick red.
3. C Carbon dioxide gas is given off and the cation gives a violet colour.
4. D The precipitate does not dissolve and the non-luminous zone of the Bunsen flame turns brick red.

From the following table:
Which pairs of cations in column (A) can be separated from each other in their aqueous solution using the reagents shown in column (B)?

1. A (1) , (2)
2. B (1) , (3)
3. C (2) , (3)
4. D (2) , (4)

From the following chart:
Which of the following is correct?

1. A Substances (B) , (C) contain trivalent cations.
2. B The cation of substance (D) gives the non-luminous zone of the Bunsen flame a brick red colour.
3. C The solution of substance (B) contains Ag⁺ ions.
4. D Solution (A) is used to precipitate the cations of analytical group I.

A sample of a calcium salt was tested separately with chloride ions, with sulphate ions and with the flame test.
Which of the following shows the results obtained under suitable conditions?

1. A With chloride ions : a precipitate forms ; with sulphate ions : no precipitate forms ; flame test : a green colour forms
2. B With chloride ions : no precipitate forms ; with sulphate ions : a precipitate forms ; flame test : a brick red colour forms
3. C With chloride ions : a precipitate forms ; with sulphate ions : no precipitate forms ; flame test : a brick red colour forms
4. D With chloride ions : no precipitate forms ; with sulphate ions : a precipitate forms ; flame test : a green colour forms

A solution contains the following cations:
Fe²⁺ , Mn²⁺ , Ag⁺ , Hg⁺ , Ca²⁺
It was treated with HCl acid, so the solution now contains the ions ..........

1. A Ag⁺ , Hg⁺ , Ca²⁺
2. B Fe²⁺ , Ag⁺
3. C Hg⁺ , Mn²⁺
4. D Fe²⁺ , Mn²⁺ , Ca²⁺

Lead(II) nitrate solution reacts with sodium bromide solution, forming precipitate (1):
(1) State the number of the analytical group of the cation of precipitate (1).
(2) What are the colour and formula of precipitate (2) formed by adding the silver cation to the anion of precipitate (1)?

When sodium chloride solution is added to a solution of salt (X), a white precipitate forms, and when conc. sulphuric acid is added to the same solid salt with heating, reddish-brown fumes are given off.
Deduce the name of salt (X).

When dilute hydrochloric acid is added to salt (X), reddish-brown fumes are given off at the mouth of the tube, and when dilute sulphuric acid is added to a solution of the same salt, a white precipitate forms of a divalent cation from the cations of analytical group I.
Deduce the name of salt (X).

What happens, «without writing reaction equations», when you add:
(1) NaOH solution to iron(II) nitrate solution.
(2) hot conc. H₂SO₄ to potassium iodide salt.

The following chart shows some chemical reactions:
(1) Deduce:
(a) the symbol of metal (X).
(b) the chemical formula of solution (Y).
(2) Show, with a symbolic equation, the effect of passing gas (Z) over magnetic iron oxide (at 650°C).

When dilute hydrochloric acid is added to solid salt (X), a gas is given off that blackens a paper moistened with lead(II) acetate solution, and when solid salt (X) is put in a Bunsen flame, the flame turns brick red.
Deduce the name of salt (X).

• When lead(II) acetate solution is added to a solution of salt (X), a white precipitate forms.
• When ammonia solution is added to a solution of salt (X), a white gelatinous precipitate forms.
Deduce the name of salt (X).

You have a solution containing the cations Fe²⁺(aq) , Ca²⁺(aq) , Pb²⁺(aq); it was divided into two parts:
(1) Which of these cations precipitates when dilute HCl acid is added to the first part of the solution?
(2) Which of the two remaining cations does not precipitate when ammonium hydroxide solution is added to the other part of the solution?

Complete the blanks of the following chart with what suits them:

From the following chart, deduce the names of each of the substances (1) : (4).

From the following chart:
Which of the following represents the cation (X²⁺)?
(Sample exam 2026)

1. A Ca²⁺
2. B Cu²⁺
3. C Mg²⁺
4. D Fe²⁺

From the experiment shown in the figure:
Which of the following represents some of the contents of test tube (B)?
(Sample exam 2026)

1. A Cl⁻(aq) , AlO₂⁻(aq) , Na⁺(aq) , Al³⁺(aq)
2. B Cl⁻(aq) , AlO₂⁻(aq) , Fe³⁺(aq) , Al(OH)₃(s)
3. C AlO₂⁻(aq) , Al³⁺(aq) , Fe³⁺(aq) , Fe(OH)₃(s)
4. D Cl⁻(aq) , AlO₂⁻(aq) , Na⁺(aq) , Fe(OH)₃(s)

Both ions of which of the following salts can be detected using the reagent of the confirmatory test of one of the cations of analytical group V?
(Sample exam 2026)

1. A MgCl₂
2. B Fe₂(SO₃)₃
3. C Pb(NO₂)₂
4. D Ba₃(PO₄)₂

Hydrochloric acid was added to a solid salt and a gas was given off that forms a black precipitate when passed into acidified copper nitrate solution.
Which of the following represents the solid salt?
(Sample exam 2026)

1. A sodium nitrite.
2. B potassium sulphide.
3. C sodium sulphite.
4. D sodium bicarbonate.

Which of the following solutions can be used to separate Fe(OH)₂ from a mixture of it with Al(OH)₃?
(Sample exam 2026)

1. A NaOH(aq)
2. B NH₄OH(aq)
3. C NaCl(aq)
4. D HCl(aq)

A mixture of the nitrates of copper(II), lead(II) and calcium.
Which of the following gives the correct order of substances that can be added to this mixture to separate each cation on its own?
(Sample exam 2026)

1. A sodium carbonate solution, then passing hydrogen sulphide gas.
2. B dilute sulphuric acid, then silver nitrate solution.
3. C hydrochloric acid, then sulphuric acid.
4. D hydrochloric acid, then sodium carbonate solution.

From the following chart:
Which of the following represents the substances (X) , (Y) , (Z)?
(Sample exam 2026)

1. A Substance (X) : AgNO₃(aq) , precipitate (Y) : AgCl(s) , precipitate (Z) : KCl(s)
2. B Substance (X) : HCl(aq) + H₂S(g) , precipitate (Y) : CuCl₂(s) , precipitate (Z) : CuCO₃(s)
3. C Substance (X) : HCl(aq) + H₂S(g) , precipitate (Y) : CuS(s) , precipitate (Z) : CuCO₃(s)
4. D Substance (X) : Na₂S(aq) , precipitate (Y) : NaCl(s) , precipitate (Z) : KCl(s)

A solution contains the ions (Cu²⁺ , K⁺ , Ag⁺)
Which of the following gives the colour of the precipitate likely to form when excess HCl solution is added, then (H₂S) gas is passed through this solution?
(Sample exam 2026)

1. A A black precipitate.
2. B A white precipitate.
3. C A mixture of a white and a black precipitate.
4. D No precipitate forms.

Two salts (A , B): the acid of salt (A) is used to detect the cation of salt (B), and the acid of salt (B) is used to detect the anion of salt (A).
Which of the following represents the two salts (A) , (B)?
(Sample exam 2026)

1. A Salt (A) : KCl , salt (B) : CuSO₄
2. B Salt (A) : Hg₂SO₄ , salt (B) : KCl
3. C Salt (A) : KCl , salt (B) : PbSO₄
4. D Salt (A) : K₂SO₄ , salt (B) : NaNO₃

A solution contains the cations (Cu²⁺ , Pb²⁺ , Ca²⁺)
Which of the following can be added to the above solution to obtain a solution containing only the copper cation?
(Sample exam 2026)

1. A Dilute sulphuric acid.
2. B Sodium carbonate solution.
3. C Sodium nitrate solution.
4. D Dilute hydrochloric acid.

Which of the solutions of the following compounds forms a precipitate with Pb(NO₃)₂(aq) but does not form a precipitate with Ba(NO₃)₂(aq)?
(Sample exam 2026)

1. A Na₂SO₄
2. B CH₃COONa
3. C NaCl
4. D Na₂CO₃

A solution contains the cations (Ag⁺ , Cu²⁺ , Pb²⁺ , Ca²⁺)
Which of the following gives the correct order of the steps needed to obtain a solution containing only the copper cation?
(Sample exam 2026)

1. A Adding hydrochloric acid – filtration – adding hydrogen sulphide gas – filtration.
2. B Adding hydrogen sulphide gas – filtration – adding hydrochloric acid – filtration.
3. C Adding sulphuric acid – filtration – adding sodium sulphide solution – filtration.
4. D Adding sodium chloride solution – filtration – adding magnesium sulphate solution – filtration.

Which of the following solutions can be added to a solution containing the cations (Al³⁺ , Fe²⁺ , Ca²⁺)
to precipitate only one of these cations?
(Sample exam 2026)

1. A Sodium carbonate.
2. B Excess sodium hydroxide.
3. C Excess ammonium hydroxide.
4. D Potassium chloride.

Which of the following does not distinguish between the main reagent for the cations of analytical group I and that of analytical group III?
(1st session 2025)

1. A Iron(II) chloride solution.
2. B Aluminium sulphate solution.
3. C Iron(III) sulphate solution.
4. D Sodium chloride solution.

When lead(II) acetate solution is added to a solution of salt (X), a white precipitate forms, and when ammonia solution is added to a solution of salt (X), a greenish-white precipitate forms.
Which of the following choices represents salt (X)?
(1st session 2025)

1. A FeSO₄
2. B Fe₂(SO₄)₃
3. C Fe(NO₃)₂
4. D Fe(HCO₃)₃

Both ions of salt (X) can be detected using reagent (Y).
Which of the following choices represents salt (X) and reagent (Y)?
(1st session 2025)

1. A Salt (X) potassium chloride, reagent (Y) conc. sulphuric acid.
2. B Salt (X) silver nitrate, reagent (Y) dilute hydrochloric acid.
3. C Salt (X) aluminium chloride, reagent (Y) sodium hydroxide solution.
4. D Salt (X) iron(III) sulphate, reagent (Y) barium hydroxide solution.

When conc. sulphuric acid is added to salt (X) with gentle heating, gas (Y) is given off and precipitate (Z) forms.
(X) , (Y) , (Z) are ..........
(Sample exam 2025)

1. A Salt (X) : Pb(NO₃)₂ , gas (Y) : NO₂ , precipitate (Z) : PbSO₄
2. B Salt (X) : Na₂CO₃ , gas (Y) : CO , precipitate (Z) : Na₂SO₄
3. C Salt (X) : KCl , gas (Y) : Cl₂ , precipitate (Z) : K₂SO₄
4. D Salt (X) : CuBr₂ , gas (Y) : Br₂ , precipitate (Z) : CuSO₄

When brown iodine solution is added to salt (A), the brown colour of the iodine disappears, and when dilute sulphuric acid is added to another amount of the same solution of salt (A), a white precipitate forms. Salt (A) is ..........
(Sample exam 2025)

1. A potassium sulphate.
2. B lead(II) thiosulphate.
3. C copper(II) sulphide.
4. D sodium nitrite.

A gas with a foul smell is passed into copper(II) chloride solution acidified with hydrochloric acid, then silver nitrate solution is added to the products of the reaction.
Which of the following choices is correct?
(2nd session 2024)

1. A A mixture of black precipitates forms.
2. B A mixture of a white precipitate and a black precipitate forms.
3. C A mixture of white precipitates forms.
4. D A mixture of a yellow precipitate and a black precipitate forms.

The following reactions take place under suitable conditions:
The two compounds (A) , (C) are ............
(2nd session 2023)

1. A Compound (A) : HCl(aq) , compound (C) : Ca(OH)₂
2. B Compound (A) : HCl(g) , compound (C) : CaCO₃
3. C Compound (A) : HCl(g) , compound (C) : Ca(OH)₂
4. D Compound (A) : HCl(aq) , compound (C) : CaCO₃

The solutions of the two salts (NH₄)₂SO₄ , MgSO₄ can be distinguished by a solution of ..........
(Trial exam / March 2023)

1. A NaNO₃
2. B KCl
3. C Na₂CO₃
4. D Ca(HCO₃)₂

Which of the following pairs of cations can be separated from their solutions using sodium chloride solution?
(1st session 2024)

1. A Ca²⁺ / Cu²⁺
2. B Hg⁺ / Pb²⁺
3. C Mg²⁺ / Ca²⁺
4. D Cu²⁺ / Pb²⁺

Dilute HCl acid is used to detect both ..........
(Trial exam / June 2021)

1. A NO₂⁻ , Hg⁺
2. B Br⁻ , Hg⁺
3. C PO₄³⁻ , Pb²⁺
4. D SO₄²⁻ , Ag⁺

Which of the following compounds is used to detect both ions of the salt lead nitrate?
(2nd session 2023)

1. A Nitric acid.
2. B Hydrochloric acid.
3. C Sulphuric acid.
4. D Carbonic acid.

When gas (X) is passed into an acidified solution of salt (Y), a black precipitate forms, and when silver nitrate solution is added to the solution of salt (Y), a white precipitate forms.
Gas (X) and salt (Y) are ..........
(2nd session 2023)

1. A Gas (X) : H₂S , salt (Y) : NaI
2. B Gas (X) : CO₂ , salt (Y) : CuCl₂
3. C Gas (X) : NO₂ , salt (Y) : MgSO₄
4. D Gas (X) : H₂S , salt (Y) : CuCl₂

When copper sulphate solution reacts with gas (A) in an acidic medium, a black precipitate forms, and when silver nitrate solution reacts with solution (B), a black precipitate also forms.
(A) , (B) are ..........
(1st session 2021)

1. A (A) : CO₂ , (B) : NaBr
2. B (A) : H₂S , (B) : NaI
3. C (A) : H₂S , (B) : Na₂S
4. D (A) : SO₂ , (B) : NaCl

When hydrogen sulphide gas is passed over copper(II) sulphate solution, the precipitate appears on ..........
(2nd session 2021)

1. A adding NaOH solution
2. B increasing the pressure.
3. C adding dilute HCl.
4. D raising the temperature.

When hydrogen sulphide gas is passed into an acidic solution of a salt, a black precipitate forms, and when barium chloride solution is added to a solution of the same salt, a white precipitate forms. The salt is ..........
(1st session 2022)

1. A Na₃PO₄
2. B CuSO₄
3. C (NH₄)₃PO₄
4. D CuCl₂

Which of the following: BaCl₂(aq) , NaOH(aq) , HCl(aq) is used to distinguish between aluminium sulphate solution and iron(II) chloride solution?
(2nd session 2023)

1. A BaCl₂(aq) , HCl(aq)
2. B NaOH(aq) only.
3. C HCl(aq) only.
4. D NaOH(aq) , BaCl₂(aq)

A student added ammonium hydroxide reagent to a solution of an iron(II) salt, and a precipitate formed whose colour was different from the expected colour.
The likely reason for this is that ..........
(1st session 2021)

1. A the reagent used is wrong.
2. B the reagent is a strong base.
3. C the reaction needs heating.
4. D the salt is mixed with other salts.

Potassium hydroxide solution was added to a solution of iron(II) sulphate prepared a long time ago in a glass beaker, and a precipitate formed whose colour is ..........
(2nd session 2022)

1. A gelatinous white.
2. B greenish-white.
3. C gelatinous green.
4. D reddish-brown.

During an experiment to detect the cation of a salt (X), a little NaOH solution was added and a precipitate formed, then more of the reagent was added and the precipitate disappeared. The solution of salt (X) is ..........
(2nd session 2021)

1. A Al(NO₃)₃
2. B FeSO₄
3. C FeCl₃
4. D CuSO₄

During an experiment to detect the cation of a salt, a little NaOH was added and a precipitate formed; on adding more NaOH, ........ forms.
(Trial exam / June 2021)

1. A NaAlO₂(aq)
2. B BaSO₄(s)
3. C NaNO₃(aq)
4. D Al(OH)₃(s)

Ammonium carbonate solution is used to distinguish between all the following cations, except ..........
(2nd session 2021)

1. A Na⁺ , Ca²⁺
2. B K⁺ , Mg²⁺
3. C Ca²⁺ , Mg²⁺
4. D K⁺ , Fe²⁺

You have the following compounds:
(1): aluminium chloride.
(2): iron(III) chloride.
(3): iron(II) chloride.
(4): hydrogen chloride.
Which of the above compounds can distinguish between sodium hydroxide and ammonium hydroxide solutions when the necessary conditions are available?
(Trial exam / May 2021)

1. A Compounds (1) , (2) , (3)
2. B Compounds (1) , (2) , (4)
3. C Compounds (2) , (3)
4. D Compounds (1) , (4)

From the following reaction chart:
The substances (X) , (Y) , (Z) are ............
(1st session 2022)

1. A (X) : FeSO₄ , (Y) : FeCl₂ , (Z) : Fe(OH)₃
2. B (X) : FeCO₃ , (Y) : FeCl₃ , (Z) : Fe(OH)₂
3. C (X) : FeCO₃ , (Y) : FeCl₂ , (Z) : Fe(OH)₂
4. D (X) : FeSO₄ , (Y) : FeCl₃ , (Z) : Fe(OH)₃

The following table shows some chemical compounds:
Which of the following choices is correct?
(1st session 2023)

1. A (D) detects the anion of (B) and the anion of (A).
2. B (C) detects the cation of (B) and the cation of (A).
3. C (A) detects the anion of (D) and the anion of (C).
4. D (B) detects the cation of (C) and the anion of (D).

From the following chart, when the reactions are carried out under suitable conditions:
The compounds (1) , (2) , (3) are ..........
(1st session 2023)

1. A Compound (1) : Pb(NO₃)₂ , compound (2) : NaHCO₃ , compound (3) : Na₂SO₄
2. B Compound (1) : Na₂SO₄ , compound (2) : NH₄NO₃ , compound (3) : K₂SO₄
3. C Compound (1) : AgNO₃ , compound (2) : (NH₄)₂CO₃ , compound (3) : Na₂SO₄
4. D Compound (1) : AgNO₃ , compound (2) : K₂SO₄ , compound (3) : KHCO₃

Using the following table:
The two salts (A) , (B) are ..........
(2nd session 2022)

1. A Salt (A) : NaNO₂ , salt (B) : FeSO₄
2. B Salt (A) : NaNO₃ , salt (B) : FeSO₄
3. C Salt (A) : NaNO₂ , salt (B) : Fe₂(SO₄)₃
4. D Salt (A) : NaNO₃ , salt (B) : Fe₂(SO₄)₃

Which of the following salts forms a precipitate and gives off a gas when hydrochloric acid is added to it under suitable conditions?
(Trial exam / March 2023)

1. A NaNO₂
2. B AgNO₃
3. C HgNO₃
4. D Pb(NO₂)₂

The following chart shows chemical reactions on some salts:
(1) Precipitate (B) is white and turns greenish-white on exposure to air.
Write the chemical formulas of each of:
1– salt (X)
2– salt (Y)
(2) State the chemical name of each of the two precipitates (A) , (B).
(Sample exam 2026)

The opposite figure shows an experiment to detect the anion of salt (X) and the cation (Z).
Study the figure well, then answer the following questions:
(1) Write the chemical formula of each of:
1– the salt (ZCl₂)
2– the black precipitate (W)
(2) Write the chemical formulas of two other salts, instead of the salt (ZCl₂), that each show the same observation, given that the anion of each of them is nitrate.
(Sample exam 2026)

In front of you are four test tubes containing solutions of different salts:
(1) Write the chemical name of the reagent used to distinguish between the solid salts of the four solutions in one experiment.
(2) Which of the four solutions gives a precipitate with excess sodium hydroxide?
(3) Which of the above solutions gives a gas and a precipitate when dilute sulphuric acid is added?
(4) Which of the above salts has a cation that cannot be detected with one of the usual reagents?
(Sample exam 2026)