A variety of ions including Na+, K+, NH4

+,
Pb2+, Fe2+, NO3
−, Cl−, Br−, S2−, and CO3
2−
are mixed in a beaker of water. If you
analyzed the precipitates, which substances
would you expect to find?
1. PbS and FeCO3
2. FeCl2 and KCl
3. NaBr and Pb(NO3)2
4. PbCO3 and NaCl
5. NaNO3 and K2S
6. FeCO3 and KNO3
7. FeS and Na2CO3

PbS and FeCO3

Well, I must say, it sounds like quite the party in that beaker! Let's see which substances you could expect to find when you analyze the precipitates:

1. PbS and FeCO3 - Ah, a classic combination of lead sulfide and iron carbonate. This would be a fascinating find, but unfortunately, it doesn't seem likely in this case.

2. FeCl2 and KCl - Ah, a little bit of iron chloride and potassium chloride. Interesting, but not quite what you would expect to find when analyzing the precipitates.

3. NaBr and Pb(NO3)2 - Ah, sodium bromide and lead nitrate. A salty and elegant mix! However, it doesn't seem like this would be the result of analyzing the precipitates.

4. PbCO3 and NaCl - Ah, lead carbonate and sodium chloride. Now this sounds like a possible combination! You might just find these substances if you analyze the precipitates.

5. NaNO3 and K2S - Ah, sodium nitrate and potassium sulfide. Now, while this combination sounds like a party in its own right, it doesn't appear to be the result of analyzing the precipitates.

6. FeCO3 and KNO3 - Ah, iron carbonate and potassium nitrate. A slightly different combination, but still not quite what you would expect to find when analyzing the precipitates.

7. FeS and Na2CO3 - Ah, the final combination! Iron sulfide and sodium carbonate. This seems like a more probable result when analyzing the precipitates.

So, my friend, the substances you would most likely find when analyzing the precipitates are PbCO3 and NaCl (option 4), as well as FeS and Na2CO3 (option 7). Enjoy your analysis and let the precipitates reveal their magical secrets!

To determine which substances would form precipitates, we need to identify the possible combination of ions that can generate insoluble compounds. Here are the step-by-step explanations for each option:

1. PbS and FeCO3:
- Pb2+ forms an insoluble compound with S2- to produce PbS, so PbS could be present as a precipitate.
- Fe2+ does not react with CO3 2-, so FeCO3 is not expected.

2. FeCl2 and KCl:
- Fe2+ does not react with Cl-, so FeCl2 is not expected.
- K+ does not form an insoluble compound with any of the provided anions.

3. NaBr and Pb(NO3)2:
- Na+ does not form insoluble compounds with any anions.
- Pb2+ forms an insoluble compound with Br- to produce PbBr2, so PbBr2 could be present as a precipitate.

4. PbCO3 and NaCl:
- Pb2+ forms an insoluble compound with CO3 2- to produce PbCO3, so PbCO3 could be present as a precipitate.
- Na+ does not form insoluble compounds with any anions.

5. NaNO3 and K2S:
- Na+ and K+ do not form insoluble compounds with any anions.
- S2- forms an insoluble compound with Pb2+ to produce PbS, but Pb2+ is not present in the provided salts.

6. FeCO3 and KNO3:
- Fe2+ does not react with CO3 2-, so FeCO3 is not expected.
- K+ does not form insoluble compounds with any anions.

7. FeS and Na2CO3:
- Fe2+ reacts with S2- to produce FeS, so FeS could be present as a precipitate.
- Na+ does not form insoluble compounds with any anions.
- CO3 2- does not react with any cations present in the mixture.

Based on the explanations above, the expected precipitates are:
- Option 1: PbS
- Option 3: PbBr2
- Option 4: PbCO3
- Option 7: FeS

Therefore, the correct answer is option 3: NaBr and Pb(NO3)2.

To determine which substances are likely to form precipitates when the given ions are mixed in water, we need to consider the solubility rules.

1. PbS and FeCO3:
According to the solubility rules, PbS (lead sulfide) and FeCO3 (iron carbonate) are both insoluble compounds. Therefore, if Pb2+ and S2- ions are present in the solution, lead sulfide (PbS) will precipitate. However, there are no sulfide ions (S2-) present, so PbS is not expected to form. Similarly, FeCO3 will not form as there are no carbonate ions (CO32-) present. Therefore, option 1 is not correct.

2. FeCl2 and KCl:
Both FeCl2 (iron chloride) and KCl (potassium chloride) are soluble compounds according to the solubility rules. Thus, they will not form precipitates. Therefore, option 2 is not correct.

3. NaBr and Pb(NO3)2:
NaBr (sodium bromide) is soluble, so it will not precipitate. Pb(NO3)2 (lead nitrate) is also soluble, therefore it will not form a precipitate. Therefore, option 3 is not correct.

4. PbCO3 and NaCl:
PbCO3 (lead carbonate) is insoluble, so if Pb2+ and CO32- ions are present, lead carbonate will form a precipitate. NaCl (sodium chloride) is soluble and will not form a precipitate. Therefore, option 4 is correct.

5. NaNO3 and K2S:
NaNO3 (sodium nitrate) and K2S (potassium sulfide) are both soluble compounds, so they will not form precipitates. Therefore, option 5 is not correct.

6. FeCO3 and KNO3:
As discussed in option 1, FeCO3 (iron carbonate) will not form a precipitate as there are no carbonate ions present. KNO3 (potassium nitrate) is also soluble and will not form a precipitate. Therefore, option 6 is not correct.

7. FeS and Na2CO3:
FeS (iron sulfide) is insoluble, so if Fe2+ and S2- ions are present, iron sulfide will precipitate. Na2CO3 (sodium carbonate) is soluble and will not form a precipitate. Therefore, option 7 is correct.

In summary, the substances you would expect to find when analyzing the precipitates are:
- PbCO3 and NaCl (option 4)
- FeS and Na2CO3 (option 7)

See the solubility rules.