The lab is for CHEM II and it is taken out of a lab paq. Below are the materials

Question

The lab is for CHEM II and it is taken out of a lab paq. Below are the materials used.

Classify your ions according to the following three groups.

Several of the cations belong to more

than one group.

Group 1: Anions that WILL NOT PRECIPITATE in the presence of

silver nitrate.

Group 2: Anions that WILL PRECIPITATE in the presence of silver

nitrate and the resulting

precipitates WILL DISSOLVE upon acidification with nitric

acid.

Group 3: Anions that WILL PRECIPITATE in the presence of silver

nitrate and the resulting

precipitates WILL NOT DISSOLVE upon acidification with nitric

acid.

A. Write a net ionic equation for any reaction that produces a

precipitate.

B. Identify the anions that produce gas upon addition of

HCl.

C. Identify the anions that do not precipitate with silver

nitrate.

D. Identify the anions that react with silver nitrate to form

precipitates that dissolve when

acidified with nitric acid.

E. Identify the anions that react with silver nitrate to form

precipitates that do not dissolve when

acidified with nitric acid.

F. What simple test (other than a specific confirmation test)

would distinguish between CO3 2-

and NO3 - ?

Here are the materials we used

1 Ammonium Molybdate, 0.2 M - 2 mL in Pipet

1 Aqueous Ammonia, 6 M, NH4OH - 4 mL in Pipet

1 Barium Chloride, 0.3 M - 2 mL in Pipet

1 Hydrochloric Acid, 6 M - 8 mL in Dropper Bottle

1 Nitric Acid, 6 M - 2.5 mL in Pipet

1 Organic Reagent - 1.5 mL in Vial

2 Pipet, Empty Short Stem

1 Silver Nitrate, 0.1 N - 6 mL in White Dropper

Bottle

1 Sodium Bromide, 0.1 M - 2.5 mL in Pipet

1 Sodium Carbonate, 0.25 M - 2.5 mL in Pipet

1 Sodium Chloride, 0.1 M - 2.5 mL in Pipet

1 Sodium Iodide, 0.1 M - 2.5 mL in Pipet

1 Sodium Phosphate, 0.1 M - 2.5 mL in Pipet

1 Sodium Sulfate, 0.1 M - 2.5 mL in Pipet

1 Sodium Sulfide, 0.1 M - 2.5 mL in Pipet

1 Unknown - 5 mL in Pipet

Explanation / Answer

add BaCl2

If there is CO32- a white precipitate of BaCO3 will appear

answer for E

Are you looking for precipitates or gases being produced. None of the compounds will form a precipitate when mixed with HCl.

What will form a gas: carbonates and sulphides: So a gas will be formed with HCl:
1) Na2CO3(aq) + 2HCl(aq) %u2192 2NaCl(aq) + CO2(g) + H2O
Remember: Carbonate + acid = salt + CO2 + H2O

2) Na2S(aq) + 2HCl (aq) %u2192 2NaCl(aq) + H2S (g)

As far as I can remember, only the precipitate Ag2CO3 - formed by the reaction of AgNO3 + Na2CO3 , will dissolve in nitric acid . All the rest form silver salts that are insoluble in HNO3

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