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Topic: Group 1 Cations, net equations and choosing reagent  (Read 9011 times)

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Offline IamWhatonearth

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Group 1 Cations, net equations and choosing reagent
« on: March 16, 2014, 08:14:51 PM »
What single reagent could you add that would allow you to differentiate between members of each pair of solid compounds below? Tell what happens to each substance when the reagent is added and write a balanced net ionic equation wherever a reaction occurs. You may use any reagent.

It says any reagent is ok but these are the ones that were used in the lab:
KI causes PbI2 to form if Pb+ is in solution, turns yellow
NH3 causes Hg2Cl2 to produce a metalic murcury
HNO3 causes Ag+ to form a white precipitate, AgCl

Questions:
1. Hg2Cl2 and HgCl2
2. AgCl and PbCl2
3. AgNO2 and AgCl
4. AgCl and Hg2Cl2
5. Hg2(NO3)2 and Hg(NO3)2
6. NH4Cl and AgCl
7. PbI2 and KI

Any help is appreciated. Thanks. c:

Offline Borek

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Re: Group 1 Cations, net equations and choosing reagent
« Reply #1 on: March 17, 2014, 03:38:29 AM »
NH3 causes Hg2Cl2 to produce a metalic murcury

If so, would adding ammonia to the solutions from the first pair allow you to decide which is which?

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HNO3 causes Ag+ to form a white precipitate, AgCl

No. HCl does.
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Offline Arkcon

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Re: Group 1 Cations, net equations and choosing reagent
« Reply #2 on: March 17, 2014, 08:40:02 AM »
We like to help people help themselves, on this forum.  You have a list, that's essentially seven different questions.  Can you use, what you know, and mentioned in your original post, to narrow down some of them.  What can you see in your seven question that yo still need help with?  Remember that you also posted:

Quote
Any help is appreciated. Thanks. c:

When you notice I've asked you for more work. 
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline IamWhatonearth

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Re: Group 1 Cations, net equations and choosing reagent
« Reply #3 on: March 18, 2014, 12:13:35 AM »
NH3 causes Hg2Cl2 to produce a metalic murcury

If so, would adding ammonia to the solutions from the first pair allow you to decide which is which?

Quote
HNO3 causes Ag+ to form a white precipitate, AgCl

No. HCl does.

You're probably right about the first one.
I forgot that HCl is added earlier in the lab. :P The flow chart says Ag(NH3)2, Cl- + HNO3 --> AgCl

I did some more work on this and here's what I have so far.
1. Hg2Cl2 and HgCl2
Use reagent NH3 for Hg2Cl2 to form a precipitate.
Hg2Cl2 (aq)+ 2NH3(aq) <--> Hg(NH2)Cl(s)
Net Ionic: Hg22+(aq) + Cl2 (aq) + 2NH3(aq) <--> 2Hg(NH2)Cl(s)

2. AgCl and PbCl2
Use KI for PbI2 to form.
PbCl2(s) + 2KI(aq) <--> PbI2(s) +2KCl(s)
Net Ionic: Pb2+(aq) + Cl2-(aq) + K+(aq) + I2-(aq)<-->PbI2(s) +2KCl(s)

3. AgNO2 and AgCl
No idea.

4. AgCl and Hg2Cl2
Use reagent NH3 for Hg2Cl2 to form a precipitate.
Hg2Cl2 (aq)+ 2NH3(aq) <--> Hg(NH2)Cl(s)
Net Ionic: Hg22+(aq) + Cl2 (aq) + 2NH3(aq) <--> 2Hg(NH2)Cl(s)

5. Hg2(NO3)2 and Hg(NO3)2
No idea.

6. NH4Cl and AgCl
No idea.

7. PbI2 and KI
No idea.

Offline AWK

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Re: Group 1 Cations, net equations and choosing reagent
« Reply #4 on: March 18, 2014, 03:25:09 AM »
3 and 6
what about solubility in cold and hot water?
7 - just look at
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Offline IamWhatonearth

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Re: Group 1 Cations, net equations and choosing reagent
« Reply #5 on: March 19, 2014, 12:46:36 AM »
I only was required to boil once and that was to disolved PbCl2. It says here that AgCl and Hg2Cl2 do not dissolve. And think that a reagent needs to be added.

Oh, you're right. PbCl2 is a solid when KI is a liquid. It doesn't need anything.

Offline AWK

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Re: Group 1 Cations, net equations and choosing reagent
« Reply #6 on: March 19, 2014, 05:22:05 AM »
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Oh, you're right. PbCl2 is a solid when KI is a liquid. It doesn't need anything.
I meant rather color of both solids
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