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Flashcards in Testing For Ions Deck (17)
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1
Q

How do you test for the copper cation (Cu 2+) and what is the ionic equation?

A

Add a few drops of hydroxide solution, if the sample contains the copper cation, then it will turn blue.
Cu + 2OH -> Cu(OH)2

2
Q

How do you test for the iron (II) cation (Fe 2+) and what is the ionic equation?

A

Add a few drops of sodium hydroxide solution, if the sample contains the iron (II) cation, then it will turn green.
Fe + 2OH -> Fe(OH)2

3
Q

How do you test for the iron (III) cation (Fe 3+) and what is the ionic equation?

A

Add a few drops of sodium hydroxide solution, if the sample contains the iron (III) cation, then it will turn brown.
Fe + 3OH -> Fe(OH)3

4
Q

How do you test for the ammonium ion (NH 4+) and what is the ionic equation?

A

Warm a sample mixed with sodium hydroxide solution and place a damp red litmus paper over the test tube. If the paper turn blue, ammonia is present and therefore the sample contains the ammonium cation (NH 4+)
NH + OH -> NH3 + H2O

5
Q

How do you test for the carbonate anion (CO3 2-) and what is the ionic equation?

A

Add hydrochloric acid. This will cause the solution to fizz and the gas coming off this will turn lime water cloudy, meaning that it is carbon dioxide and hence the substance was carbonate.
CO3 + 2H -> CO2 + H2O

6
Q

How do you test for the chloride anion (Cl -) and what is the ionic equation?

A

To a sample, add nitric acid and then silver nitrate solution. If there is a white precipitate, then the substance contains the chloride anion.
Cl + Ag -> AgCl

7
Q

How do you test for the bromide anion (Br -) and what is the ionic equation?

A

To a sample, add nitric acid and then silver nitrate solution. If there is a cream precipitate, then the substance contains the bromide anion.
Br + Ag -> AgBr

8
Q

How do you test for the iodide anion (I -) and what is the ionic equation?

A

To a sample, add nitric acid and then silver nitrate solution. If there is a yellow precipitate, then the substance contains the iodide anion.
I + Ag -> AgI

9
Q

How do you test for the sulphate anion (SO4 2-) and what is the ionic equation?

A

To a sample, add hydrochloric acid and then barium chloride solution. If there is a white precipitate, then the substance contains the sulphate anion.
SO4 + Ba -> BaSO4

10
Q

Why does nitric acid have to be added before the silver nitrate when testing for the chloride, bromide or iodide anion and also hydrochloric acid before barium chloride when testing for sulphate anions?

A

The nitric acid and the hydrochloric acid eliminate other anions that also form a precipitate with silver nitrate or barium chloride.

11
Q

What are the solubility rules?

A

Sodium, potassium, ammonium, nitrates, sulphates and chlorides are all soluble except CaSO4, BaSO4, PbSO4, AgCl and PbCl.
Carbonates are all insoluble except for Na +, K + and NH4 +.

12
Q

How do you test for metal ions, using flame tests?

A

Dip a nichrome wire in hydrochloride acid and then put it in the flame to clean it. Dip it into hydrochloride acid again and then into the substance. Heat the wire in a non-roaring, non-luminous Bunsen flame and note the flame colour.

13
Q

How do you test for potassium ion, K+?

A

The flame test should be conducted and the flame will turn lilac

14
Q

How do you test for the sodium ion, Na+?

A

The flame test should be conducted and the flame will turn yellow

15
Q

How do you test for the lithium ion, Li+?

A

The flame test should be conducted and the flame will turn red

16
Q

How do you test for the calcium ion, Ca+?

A

The flame test should be conducted and the flame will turn orange-red

17
Q

How do you test for the copper ion, Cu2+?

A

The flame test should be conducted and the flame will turn blue-green.