Consider the following reaction:

PbCl2 + 2 NaOH -> Pb(OH)2 + 2 NaCl
What would be the major species observed
floating in solution after one mole of PbCl2
and 2 moles of NaOH are mixed in aqueous
solution?
1. Na+ ions, Cl− ions and H+ ions
2. Pb2+ ions, Cl− ions and Na+ ions
3. Pb2+ ions, Cl− ions, Na+ ions and OH−
ions
4. Pb2+ ions, Cl− ions, Na+ ions, H+ ions
and OH− ions
5. Cl− ions and Na+ ions
6. Pb2+ ions, Na+ ions and OH− ions
7. Na+ and OH− ions

8. Dancing unicorns and exploding cupcakes

Hmm, let's think about this. In the given reaction, PbCl2 reacts with NaOH to form Pb(OH)2 and NaCl.

So, after the reaction, the major species observed floating in the solution would be:
- Pb2+ ions from PbCl2
- Cl- ions from PbCl2 and NaCl
- Na+ ions from NaOH and NaCl
- OH- ions from NaOH

Therefore, the correct answer would be option 3: Pb2+ ions, Cl- ions, Na+ ions, and OH- ions.

To determine the major species observed floating in solution after the reaction between PbCl2 and NaOH, we need to analyze the reaction and identify the products formed.

The balanced chemical equation for the reaction is:
PbCl2 + 2 NaOH -> Pb(OH)2 + 2 NaCl

From the equation, we can see that PbCl2 reacts with NaOH to form Pb(OH)2 and NaCl as the products.

Therefore, the major species observed floating in solution after the reaction would be:
- Pb2+ ions (from Pb(OH)2)
- Cl− ions (from PbCl2 and NaCl)
- Na+ ions (from NaOH and NaCl)
- OH− ions (from NaOH)

So, the correct answer would be option 3. Pb2+ ions, Cl− ions, Na+ ions, and OH− ions.

To determine the major species observed floating in the solution after the reaction, we first need to balance the equation. By balancing the equation:

PbCl2 + 2 NaOH -> Pb(OH)2 + 2 NaCl

We can see that for every one mole of PbCl2, two moles of NaOH are required. This means that if we have one mole of PbCl2 and two moles of NaOH, we will have a complete reaction with no excess of either reactant.

Based on the balanced equation, we can identify the major species observed in the solution as follows:

- Pb2+ ions: One mole of PbCl2 reacts to form one mole of Pb(OH)2, so we will have Pb2+ ions in the solution.
- Na+ ions: Two moles of NaOH are required for the reaction, so we will have two moles of Na+ ions in the solution.
- Cl- ions: One mole of PbCl2 reacts to form one mole of NaCl, so we will have one mole of Cl- ions in the solution.
- OH- ions: Two moles of NaOH react to form two moles of NaCl, so we will have two moles of OH- ions in the solution.

From the above analysis, the major species observed floating in the solution after one mole of PbCl2 and two moles of NaOH are mixed in aqueous solution include Pb2+ ions, Na+ ions, Cl- ions, and OH- ions.

Therefore, the correct answer is option 3: Pb2+ ions, Cl- ions, Na+ ions, and OH- ions.

I don't know what this problem is driving at BUT it doesn't make any sense to me. You will not be able to SEE any of these ions floating around anywhere.