Inorganic Chemistry: Qualitative Analysis Flashcards

Question 1

Q

Aqueous sodium hydroxide is added dropwise to a solution containing Al³⁺ ions. What is observed and what happens in excess?

Answer

A

White ppt, dissolves in excess

Aluminium hydroxide forms then dissolves due to amphoteric behaviour forming [Al(OH)₄]^-.

Question 2

Q

Aqueous sodium hydroxide is added to Cu²⁺ ions. What colour precipitate forms?

Answer

A

Blue ppt

Copper(II) hydroxide forms and is insoluble in excess NaOH.

Question 3

Q

Aqueous ammonia is added to Zn²⁺ ions. What happens initially and in excess?

Answer

A

White ppt, dissolves in excess

Zinc hydroxide forms then dissolves forming a colourless ammine complex.

Question 4

Q

True or False:

A green precipitate with NaOH that is insoluble in excess suggests Fe³⁺ ions.

Answer

A

False

Fe²⁺ gives green ppt; Fe³⁺ gives brown ppt.

Question 5

Q

Aqueous sodium hydroxide added to Fe²⁺ ions gives what observation?

Answer

A

Green ppt

Iron(II) hydroxide forms and slowly turns brown due to oxidation.

Question 6

Q

Aqueous sodium hydroxide added to Fe³⁺ ions gives what observation?

Answer

A

Brown ppt

Iron(III) hydroxide forms and is insoluble in excess.

Question 7

Q

Fill in the blank:

When testing for ammonium ions, warming with sodium hydroxide releases _____ gas.

Answer

A

Ammonia

Ammonia turns damp red litmus paper blue.

Question 8

Q

What reagent is used to confirm the presence of ammonia gas?

Answer

A

Damp red litmus paper

It turns blue in the presence of ammonia.

Question 9

Q

True or False:

Ammonia gas turns damp blue litmus paper red.

Answer

A

False

It is alkaline, so turns red litmus blue.

Question 10

Q

What reagent is used to test for carbonate ions?

Answer

A

Dilute acid

Carbonates react to produce CO₂ gas.

Question 11

Q

What observation confirms carbon dioxide gas?

Answer

A

Turns limewater milky

Formation of CaCO₃ precipitate.

Question 12

Q

True or False:

Sulfate ions produce a white precipitate with acidified barium chloride solution.

Answer

A

True

BaSO₄ is insoluble and forms a white precipitate.

Question 13

Q

Why is barium chloride acidified in the sulfate test?

Answer

A

To remove CO₃^2- interference

Acid reacts with carbonates preventing false positives.

Question 14

Q

What reagent is used to test for halide ions?

Answer

A

Acidified silver nitrate

Produces silver halide precipitates.

Question 15

Q

What colour precipitate indicates chloride ions?

Answer

A

White ppt

AgCl forms and dissolves in dilute ammonia.

Question 16

Q

What colour precipitate indicates bromide ions?

Answer

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A

Cream ppt

AgBr forms and dissolves in concentrated ammonia.

Question 17

Q

What colour precipitate indicates iodide ions?

Answer

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A

Yellow ppt

AgI forms and is insoluble in ammonia.

Question 18

Q

True or False:

Silver iodide dissolves in dilute ammonia solution.

Answer

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A

False

AgI is insoluble even in concentrated ammonia.

Question 19

Q

What gas is produced when nitrate ions are reduced with aluminium in alkaline solution?

Answer

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A

Ammonia

Devarda’s test produces NH₃ from NO₃^-.

Question 20

Q

What is observed when chlorine water is added to iodide ions?

Answer

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A

Brown solution

Iodine is displaced, showing halogen reactivity trends.

Inorganic Chemistry: Qualitative Analysis Flashcards

Identify ions and compounds using chemical tests and observations. (20 cards)