The spectator ions in the precipitation equation Pb(NO3)2+ 2KI --> PbI2 + 2KNO3 are ________.
The Attempt at a Solution
I've been working through a lot of practice problems for next week's final exam, and I seem to be struggling with this concept.
I know the spectator ions 'do nothing', so I am thinking that means they are the ones that are unchanged. That logic got me through most of them, but not this last one.
Here is what I have been doing to solve them (which I know does not yield the correct answer):
I added the charges:
Pb+2 (NO3+)2+ 2K+I- --> Pb+2I-2 + 2K+NO-3
and then I note what each one does:
Pb+2 --> Pb+2
(NO3+)2 --> NO-3
2K+ --> 2K+
2I- --> I-2
So from that logic I would assume that
Pb+2 and 2K+
are the spectator ions (because they did not change), which is not an answer choice.
What did I do wrong?