Qualitative Analysis: Cations, Anions, Gases and Flame Tests

1. A colourless solution gives a white precipitate with aqueous sodium hydroxide. The precipitate dissolves in excess sodium hydroxide. With aqueous ammonia, a white precipitate forms and does not dissolve in excess.

Which ion is most likely present?

A Al3+
B Zn2+
C Ca2+
D Cu2+

2. A solution gives a white precipitate with aqueous sodium hydroxide. The precipitate dissolves in excess sodium hydroxide. With aqueous ammonia, the white precipitate also dissolves in excess.

Which ion is present?

A Al3+
B Zn2+
C Pb2+
D Ca2+

3. A pale green precipitate forms when aqueous sodium hydroxide is added to a solution. On standing in air, the precipitate slowly turns brown.

Which ion is present?

A Fe2+
B Fe3+
C Cu2+
D Zn2+

4. A reddish-brown precipitate forms when aqueous sodium hydroxide is added to a solution. The precipitate does not dissolve in excess sodium hydroxide.

Which ion is present?

A Fe2+
B Fe3+
C Al3+
D Ca2+

5. A blue solution gives a light blue precipitate with aqueous sodium hydroxide. With excess aqueous ammonia, a deep blue solution forms.

Which ion is present?

A Fe2+
B Fe3+
C Cu2+
D Zn2+

6. A solution gives no precipitate with aqueous ammonia but gives a white precipitate with aqueous sodium hydroxide.

Which ion is most likely present?

A Ca2+
B Zn2+
C Al3+
D Cu2+

7. A salt is warmed with aqueous sodium hydroxide. A gas is produced that turns damp red litmus paper blue.

Which ion is present in the salt?

A NH4+
B NO3–
C CO3 2–
D SO4 2–

8. A student adds dilute nitric acid to an unknown solid. Effervescence occurs. The gas turns limewater milky.

Which ion is present?

A chloride
B carbonate
C sulfate
D nitrate

9. A solution is acidified with dilute nitric acid. Aqueous silver nitrate is added and a white precipitate forms.

Which ion is present?

A Cl–
B Br–
C I–
D SO4 2–

10. A solution is acidified with dilute nitric acid. Aqueous silver nitrate is added and a cream precipitate forms.

Which ion is present?

A Cl–
B Br–
C I–
D NO3–

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

11. A solution is acidified with dilute nitric acid. Aqueous silver nitrate is added and a yellow precipitate forms.

Which ion is present?

A Cl–
B Br–
C I–
D CO3 2–

12. A solution is acidified with dilute hydrochloric acid. Aqueous barium chloride is added and a white precipitate forms.

Which ion is present?

A SO4 2–
B CO3 2–
C Cl–
D NO3–

13. Why is dilute nitric acid added before testing for chloride ions with silver nitrate?

A To produce chlorine gas from chloride ions.
B To remove carbonate ions that could also form a precipitate.
C To make silver chloride more soluble.
D To neutralise silver nitrate.

14. Why is dilute hydrochloric acid added before testing for sulfate ions with barium chloride?

A To remove carbonate ions that could also give a white precipitate.
B To form barium sulfate before adding barium chloride.
C To make sulfate ions more reactive by oxidation.
D To make all salts insoluble.

15. A gas relights a glowing splint.

Which gas is present?

A hydrogen
B oxygen
C carbon dioxide
D ammonia

16. A gas burns with a squeaky pop when a lighted splint is applied.

Which gas is present?

A hydrogen
B oxygen
C carbon dioxide
D chlorine

17. A gas turns damp red litmus paper blue.

Which gas is present?

A ammonia
B chlorine
C sulfur dioxide
D carbon dioxide

18. A gas bleaches damp litmus paper.

Which gas is present?

A hydrogen
B chlorine
C oxygen
D ammonia

19. A gas turns limewater milky.

Which gas is present?

A carbon dioxide
B hydrogen
C ammonia
D oxygen

20. A gas has a choking smell and decolourises acidified potassium manganate(VII) solution.

Which gas is present?

A ammonia
B sulfur dioxide
C oxygen
D hydrogen

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

21. A flame test on a solid gives a lilac flame.

Which ion is present?

A Li+
B Na+
C K+
D Ca2+

22. A flame test gives a brick-red flame.

Which ion is present?

A Li+
B Ca2+
C Cu2+
D Na+

23. A flame test gives a yellow flame.

Which ion is present?

A Na+
B K+
C Ca2+
D Cu2+

24. A flame test gives a blue-green flame.

Which ion is present?

A Ca2+
B Cu2+
C Na+
D Li+

25. A flame test gives a red/crimson flame.

Which ion is most likely present?

A Li+
B Na+
C K+
D Cu2+

26. A white solid dissolves in water. The solution gives a white precipitate with aqueous sodium hydroxide, soluble in excess. It gives no deep blue colour with excess aqueous ammonia.

Which ion is most likely present?

A Cu2+
B Al3+
C Fe2+
D Fe3+

27. A solution gives a white precipitate with aqueous sodium hydroxide that dissolves in excess. It also gives a white precipitate with aqueous ammonia that dissolves in excess.

Which pair of reagents best confirms the cation?

A sodium hydroxide only
B ammonia only
C sodium hydroxide and ammonia together
D hydrochloric acid and silver nitrate

28. A solid gives ammonia when warmed with sodium hydroxide. A separate sample gives a white precipitate with acidified barium chloride.

Which salt could it be?

A ammonium sulfate
B ammonium chloride
C sodium sulfate
D calcium carbonate

29. A salt gives a yellow precipitate with acidified silver nitrate. It also gives a lilac flame test.

Which salt is most likely?

A sodium chloride
B potassium iodide
C potassium bromide
D lithium iodide

30. A salt gives a cream precipitate with acidified silver nitrate and a yellow flame test.

Which salt is most likely?

A sodium bromide
B sodium chloride
C potassium bromide
D calcium iodide

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

31. A salt gives a white precipitate with acidified silver nitrate and a brick-red flame test.

Which salt is most likely?

A calcium chloride
B calcium sulfate
C sodium chloride
D potassium chloride

32. A solution contains two cations. When aqueous sodium hydroxide is added slowly, a green precipitate forms. With more sodium hydroxide, a white precipitate forms and then dissolves.

Which two ions could be present?

A Fe2+ and Al3+
B Fe3+ and Cu2+
C Cu2+ and Ca2+
D Zn2+ and NH4+

33. A solution contains two anions. Addition of dilute nitric acid causes effervescence. After effervescence stops, addition of aqueous silver nitrate gives a white precipitate.

Which ions are present?

A carbonate and chloride
B sulfate and chloride
C nitrate and carbonate
D bromide and sulfate

34. A student tests a solution with aqueous sodium hydroxide and sees a white precipitate. The precipitate does not dissolve in excess sodium hydroxide. On warming with sodium hydroxide, no gas is produced.

Which ion is most likely present?

A Ca2+
B Al3+
C NH4+
D Zn2+

35. A student adds aqueous sodium hydroxide to a solution containing Fe2+ and Cu2+ ions.

Which observation is expected?

A only a white precipitate
B only a reddish-brown precipitate
C green and light blue precipitates
D deep blue solution only

36. A solution gives a white precipitate with aqueous sodium hydroxide. The precipitate dissolves in excess. With aqueous ammonia, a white precipitate forms and dissolves in excess.

Which cation is present, and what is the key observation that distinguishes it from aluminium?

A Zn2+; dissolves in excess ammonia
B Zn2+; does not dissolve in excess ammonia
C Al3+; dissolves in excess ammonia
D Al3+; forms a blue precipitate

37. A solution gives a white precipitate with aqueous sodium hydroxide, insoluble in excess. It gives no precipitate with aqueous ammonia.

Which ion is most likely present?

A Ca2+
B Zn2+
C Pb2+
D Al3+

38. Which set of tests would best identify ammonium chloride?

A warm with NaOH; add acidified AgNO3 to a fresh solution
B add acidified BaCl2; do a flame test
C add dilute acid; test gas with limewater
D add aqueous ammonia; add excess sodium hydroxide

39. Which set of observations identifies copper(II) sulfate?

A blue solution; white precipitate with acidified barium chloride; deep blue solution with excess ammonia
B colourless solution; white precipitate with acidified silver nitrate; yellow flame
C green precipitate with sodium hydroxide; cream precipitate with silver nitrate
D lilac flame; gas produced with sodium hydroxide on warming

40. Which result would not be expected for iron(III) chloride solution?

A reddish-brown precipitate with sodium hydroxide
B reddish-brown precipitate with aqueous ammonia
C white precipitate with acidified silver nitrate
D deep blue solution with excess ammonia

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

41. A colourless solution gives no precipitate with sodium hydroxide at room temperature. On warming with sodium hydroxide and aluminium foil, ammonia is produced.

Which ion is present?

A nitrate
B sulfate
C chloride
D carbonate

42. Which reagent is used to test for nitrate ions in solution?

A aqueous silver nitrate after acidifying with nitric acid
B aqueous barium chloride after acidifying with hydrochloric acid
C aqueous sodium hydroxide and aluminium foil, warmed
D limewater after adding dilute acid

43. A solid reacts with dilute acid to produce a gas. The same solid gives a brick-red flame.

Which solid could be present?

A calcium carbonate
B sodium sulfate
C potassium chloride
D copper(II) oxide

44. A solution gives a white precipitate with aqueous ammonia. The precipitate does not dissolve in excess ammonia, but dissolves in excess sodium hydroxide.

Which cation is present?

A Al3+
B Zn2+
C Cu2+
D Fe2+

45. A solution gives a white precipitate with aqueous sodium hydroxide. The precipitate dissolves in excess. Addition of dilute hydrochloric acid to a fresh sample gives a white precipitate.

Which cation is most likely present?

A Al3+
B Zn2+
C Pb2+
D Ca2+

46. Which pair of ions cannot be distinguished using only aqueous sodium hydroxide?

A Fe2+ and Fe3+
B Cu2+ and Fe2+
C Al3+ and Pb2+
D Cu2+ and Zn2+

47. Which pair of ions can be distinguished using aqueous ammonia but not clearly by aqueous sodium hydroxide alone?

A Al3+ and Zn2+
B Fe2+ and Fe3+
C Cu2+ and Fe3+
D Ca2+ and Cu2+

48. A solution gives a white precipitate with acidified silver nitrate. The precipitate dissolves in dilute aqueous ammonia.

Which ion is present?

A Cl–
B Br–
C I–
D SO4 2–

49. A solution gives a cream precipitate with acidified silver nitrate. The precipitate dissolves only in concentrated aqueous ammonia.

Which ion is present?

A chloride
B bromide
C iodide
D sulfate

50. A solution gives a yellow precipitate with acidified silver nitrate. The precipitate is insoluble in aqueous ammonia.

Which ion is present?

A chloride
B bromide
C iodide
D nitrate

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

1. A

A right: Al3+ gives a white precipitate with NaOH that dissolves in excess, but with ammonia the white precipitate does not dissolve.
B wrong: Zn2+ dissolves in excess NaOH and excess ammonia.
C wrong: Ca2+ gives a white precipitate with NaOH but does not dissolve in excess.
D wrong: Cu2+ gives a blue precipitate, not white.

2. B

A wrong: Al3+ does not dissolve in excess ammonia.
B right: Zn2+ gives a white precipitate that dissolves in excess NaOH and excess ammonia.
C wrong: Pb2+ dissolves in excess NaOH but not in excess ammonia.
D wrong: Ca2+ does not dissolve in excess NaOH and gives no precipitate with ammonia.

3. A

A right: Fe2+ gives a pale green precipitate, Fe(OH)2, which turns brown on standing due to oxidation.
B wrong: Fe3+ gives a reddish-brown precipitate immediately.
C wrong: Cu2+ gives a light blue precipitate.
D wrong: Zn2+ gives a white precipitate.

4. B

A wrong: Fe2+ gives green precipitate.
B right: Fe3+ gives reddish-brown Fe(OH)3, insoluble in excess NaOH.
C wrong: Al3+ gives a white precipitate soluble in excess NaOH.
D wrong: Ca2+ gives a white precipitate.

5. C

A wrong: Fe2+ gives green precipitate.
B wrong: Fe3+ gives reddish-brown precipitate.
C right: Cu2+ gives a light blue precipitate with NaOH and a deep blue solution with excess ammonia.
D wrong: Zn2+ gives white precipitate, not blue.

6. A

A right: Ca2+ gives no precipitate with aqueous ammonia but gives a white precipitate with NaOH.
B wrong: Zn2+ gives a white precipitate with ammonia, soluble in excess.
C wrong: Al3+ gives a white precipitate with ammonia.
D wrong: Cu2+ gives blue precipitate with ammonia.

7. A

A right: NH4+ ions produce ammonia gas when warmed with NaOH; ammonia turns damp red litmus blue.
B wrong: Nitrate needs NaOH + aluminium foil to produce ammonia.
C wrong: Carbonate gives carbon dioxide with acid.
D wrong: Sulfate gives white precipitate with acidified barium ions.

8. B

A wrong: Chlorides give precipitates with silver nitrate.
B right: Carbonates react with acid to produce CO2, which turns limewater milky.
C wrong: Sulfates are tested using acidified barium chloride.
D wrong: Nitrates do not give CO2 with acid.

9. A

A right: Chloride ions give a white precipitate of silver chloride with acidified silver nitrate.
B wrong: Bromide gives cream precipitate.
C wrong: Iodide gives yellow precipitate.
D wrong: Sulfate is tested with barium chloride, not silver nitrate.

10. B

A wrong: Chloride gives white precipitate.
B right: Bromide gives cream precipitate.
C wrong: Iodide gives yellow precipitate.
D wrong: Nitrate gives no precipitate with silver nitrate.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

11. C

A wrong: Chloride gives white precipitate.
B wrong: Bromide gives cream precipitate.
C right: Iodide gives yellow precipitate with acidified silver nitrate.
D wrong: Carbonate should be removed by acidification and is not the halide answer.

12. A

A right: Sulfate ions give a white precipitate of barium sulfate with acidified barium chloride.
B wrong: Carbonates are removed by acidification.
C wrong: Chloride is tested with silver nitrate.
D wrong: Nitrates do not give this precipitate.

13. B

A wrong: Nitric acid does not produce chlorine gas in this test.
B right: Nitric acid removes carbonate ions, which could otherwise form a misleading precipitate with silver ions.
C wrong: Nitric acid does not make silver chloride more soluble.
D wrong: It is not used to neutralise silver nitrate.

14. A

A right: Hydrochloric acid removes carbonate ions because carbonates could also give a white precipitate with barium ions.
B wrong: Barium sulfate forms after adding barium chloride.
C wrong: Sulfate is not oxidised in this test.
D wrong: Acid does not make all salts insoluble.

15. B

A wrong: Hydrogen gives a squeaky pop with a lighted splint.
B right: Oxygen relights a glowing splint.
C wrong: Carbon dioxide turns limewater milky and puts out flames.
D wrong: Ammonia turns damp red litmus blue.

16. A

A right: Hydrogen burns with a squeaky pop.
B wrong: Oxygen relights a glowing splint.
C wrong: Carbon dioxide turns limewater milky.
D wrong: Chlorine bleaches damp litmus paper.

17. A

A right: Ammonia is alkaline and turns damp red litmus blue.
B wrong: Chlorine bleaches damp litmus.
C wrong: Sulfur dioxide decolourises acidified potassium manganate(VII).
D wrong: Carbon dioxide turns limewater milky.

18. B

A wrong: Hydrogen gives a squeaky pop.
B right: Chlorine bleaches damp litmus paper.
C wrong: Oxygen relights a glowing splint.
D wrong: Ammonia turns red litmus blue.

19. A

A right: Carbon dioxide turns limewater milky.
B wrong: Hydrogen gives squeaky pop.
C wrong: Ammonia turns damp red litmus blue.
D wrong: Oxygen relights a glowing splint.

20. B

A wrong: Ammonia turns damp red litmus blue.
B right: Sulfur dioxide has a choking smell and decolourises acidified potassium manganate(VII).
C wrong: Oxygen relights a glowing splint.
D wrong: Hydrogen gives a squeaky pop.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

21. C

A wrong: Li+ gives red/crimson flame.
B wrong: Na+ gives yellow flame.
C right: K+ gives lilac flame.
D wrong: Ca2+ gives brick-red flame.

22. B

A wrong: Li+ gives crimson flame.
B right: Ca2+ gives brick-red flame.
C wrong: Cu2+ gives blue-green flame.
D wrong: Na+ gives yellow flame.

23. A

A right: Na+ gives yellow flame.
B wrong: K+ gives lilac flame.
C wrong: Ca2+ gives brick-red flame.
D wrong: Cu2+ gives blue-green flame.

24. B

A wrong: Ca2+ gives brick-red flame.
B right: Cu2+ gives blue-green flame.
C wrong: Na+ gives yellow flame.
D wrong: Li+ gives crimson flame.

25. A

A right: Li+ gives red/crimson flame.
B wrong: Na+ gives yellow flame.
C wrong: K+ gives lilac flame.
D wrong: Cu2+ gives blue-green flame.

26. B

A wrong: Cu2+ would give a blue precipitate and deep blue solution with excess ammonia.
B right: Al3+ gives a white precipitate with NaOH soluble in excess; it does not give deep blue with ammonia.
C wrong: Fe2+ gives green precipitate.
D wrong: Fe3+ gives reddish-brown precipitate.

27. C

A wrong: Sodium hydroxide alone cannot clearly separate all white-precipitate ions.
B wrong: Ammonia alone is not always enough.
C right: Zn2+ is confirmed by white precipitate soluble in excess NaOH and soluble in excess ammonia.
D wrong: Hydrochloric acid and silver nitrate test anions, not this cation.

28. A

A right: NH4+ gives ammonia with NaOH; SO4 2– gives white precipitate with acidified barium chloride, so ammonium sulfate fits.
B wrong: Ammonium chloride gives ammonia but not sulfate test.
C wrong: Sodium sulfate gives sulfate test but no ammonia with NaOH.
D wrong: Calcium carbonate gives CO2 with acid, not these results.

29. B

A wrong: Sodium chloride gives white precipitate and yellow flame.
B right: Potassium iodide gives yellow silver iodide precipitate and lilac potassium flame.
C wrong: Potassium bromide gives cream precipitate, not yellow.
D wrong: Lithium iodide gives crimson flame, not lilac.

30. A

A right: Sodium bromide gives cream silver bromide precipitate and yellow sodium flame.
B wrong: Sodium chloride gives white precipitate.
C wrong: Potassium bromide gives lilac flame.
D wrong: Calcium iodide gives yellow precipitate and brick-red flame.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

31. A

A right: Calcium chloride gives white silver chloride precipitate and brick-red calcium flame.
B wrong: Calcium sulfate would not give chloride test.
C wrong: Sodium chloride gives yellow flame.
D wrong: Potassium chloride gives lilac flame.

32. A

A right: Fe2+ gives green precipitate; Al3+ gives white precipitate soluble in excess NaOH.
B wrong: Fe3+ gives reddish-brown; Cu2+ gives blue.
C wrong: Cu2+ gives blue and Ca2+ white insoluble.
D wrong: Zn2+ gives white soluble, NH4+ gives ammonia on warming, not green precipitate.

33. A

A right: Carbonate causes effervescence with nitric acid; chloride then gives white precipitate with silver nitrate.
B wrong: Sulfate does not effervesce with acid.
C wrong: Nitrate gives no silver nitrate precipitate.
D wrong: Bromide gives cream precipitate, sulfate no effervescence.

34. A

A right: Ca2+ gives a white precipitate with NaOH, insoluble in excess; no ammonia gas on warming.
B wrong: Al3+ precipitate dissolves in excess NaOH.
C wrong: NH4+ gives ammonia gas when warmed with NaOH.
D wrong: Zn2+ precipitate dissolves in excess NaOH.

35. C

A wrong: Fe2+ and Cu2+ do not give white precipitates.
B wrong: Fe3+ gives reddish-brown, not Fe2+.
C right: Fe2+ gives green precipitate and Cu2+ gives light blue precipitate.
D wrong: Deep blue solution forms with excess ammonia and Cu2+, not with NaOH.

36. A

A right: Zn2+ is distinguished from Al3+ because its white precipitate dissolves in excess ammonia.
B wrong: Zn2+ does dissolve in excess ammonia.
C wrong: Al3+ does not dissolve in excess ammonia.
D wrong: Al3+ does not form a blue precipitate.

37. A

A right: Ca2+ gives white precipitate with NaOH, insoluble in excess, and usually no precipitate with ammonia.
B wrong: Zn2+ precipitate dissolves in excess NaOH and gives precipitate with ammonia.
C wrong: Pb2+ gives white precipitate soluble in excess NaOH, not no precipitate with ammonia.
D wrong: Al3+ dissolves in excess NaOH and gives precipitate with ammonia.

38. A

A right: Warm with NaOH tests NH4+; acidified AgNO3 tests Cl–. Together they identify ammonium chloride.
B wrong: BaCl2 tests sulfate, flame test tests metal ions.
C wrong: Acid + limewater tests carbonate.
D wrong: Ammonia/NaOH mainly test cations.

39. A

A right: Copper(II) sulfate is blue, gives white BaSO4 with acidified barium chloride, and forms deep blue solution with excess ammonia.
B wrong: Chloride and sodium, not copper sulfate.
C wrong: Fe2+ and bromide-type observations.
D wrong: Potassium and ammonium-type observations.

40. D

A wrong: Fe3+ gives reddish-brown precipitate with sodium hydroxide; expected.
B wrong: Fe3+ gives reddish-brown precipitate with ammonia; expected.
C wrong: Chloride ions give white precipitate with acidified silver nitrate; expected.
D right: Deep blue solution with excess ammonia is expected for Cu2+, not Fe3+.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.

41. A

A right: Nitrate ions produce ammonia when warmed with sodium hydroxide and aluminium foil.
B wrong: Sulfate gives white precipitate with acidified barium chloride.
C wrong: Chloride gives white precipitate with acidified silver nitrate.
D wrong: Carbonate gives CO2 with acid.

42. C

A wrong: This tests halide ions.
B wrong: This tests sulfate ions.
C right: Nitrate ions are tested by warming with aqueous sodium hydroxide and aluminium foil; ammonia is produced.
D wrong: This tests carbonate ions through carbon dioxide.

43. A

A right: Calcium carbonate reacts with acid to produce CO2 and gives brick-red calcium flame.
B wrong: Sodium sulfate gives yellow flame but no gas with acid.
C wrong: Potassium chloride gives lilac flame and no gas with acid.
D wrong: Copper(II) oxide reacts with acid but gives no gas.

44. A

A right: Al3+ gives white precipitate with ammonia insoluble in excess; its hydroxide dissolves in excess sodium hydroxide.
B wrong: Zn2+ dissolves in excess ammonia.
C wrong: Cu2+ gives blue precipitate/deep blue solution.
D wrong: Fe2+ gives green precipitate.

45. C

A wrong: Al3+ gives white precipitate with NaOH soluble in excess, but dilute HCl does not give a white precipitate with Al3+.
B wrong: Zn2+ does not give a white precipitate with dilute HCl.
C right: Pb2+ gives white precipitate with NaOH soluble in excess, and also gives white PbCl2 precipitate with dilute HCl.
D wrong: Ca2+ precipitate with NaOH is insoluble in excess.

46. C

A wrong: Fe2+ gives green; Fe3+ gives reddish-brown.
B wrong: Cu2+ gives blue; Fe2+ gives green.
C right: Al3+ and Pb2+ both give white precipitates soluble in excess NaOH, so NaOH alone cannot distinguish them clearly.
D wrong: Cu2+ gives blue; Zn2+ gives white soluble in excess.

47. A

A right: Al3+ and Zn2+ both give white precipitates soluble in excess NaOH, but only Zn2+ dissolves in excess ammonia.
B wrong: Fe2+ and Fe3+ are clearly distinguished by NaOH colours.
C wrong: Cu2+ and Fe3+ are distinguished by colour with NaOH.
D wrong: Ca2+ and Cu2+ are easily distinguished by NaOH/ammonia observations.

48. A

A right: Silver chloride is white and dissolves in dilute aqueous ammonia.
B wrong: Silver bromide is cream and dissolves only in concentrated ammonia.
C wrong: Silver iodide is yellow and insoluble in ammonia.
D wrong: Sulfate is tested with barium chloride.

49. B

A wrong: Chloride gives white precipitate soluble in dilute ammonia.
B right: Bromide gives cream precipitate soluble only in concentrated ammonia.
C wrong: Iodide gives yellow precipitate insoluble in ammonia.
D wrong: Sulfate does not give cream silver halide precipitate.

50. C

A wrong: Chloride gives white precipitate.
B wrong: Bromide gives cream precipitate.
C right: Iodide gives yellow precipitate insoluble in ammonia.
D wrong: Nitrate gives no such precipitate.

Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 11 World Records and 7 Distinctions, Educate A Change.