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Topic: Will Calcium hydroxie form?  (Read 4713 times)

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Offline jonjon1324

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Will Calcium hydroxie form?
« on: October 02, 2010, 07:36:18 PM »
I was asked if NH3 solution is mixed with 0.5 CaCl2, should Ca(OH)2 form? Make a prediction based on the fact that the pH of 1 M NH3 is about 11.6? The answer is that it SHOULDN'T form, but I have NO idea why...I know Nh3 is a weak base and CaCl2 is an acidic solution, but I don't understand how I can tell whether Ca(OH)2 can form or not..

Offline ooosh

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Re: Will Calcium hydroxie form?
« Reply #1 on: October 02, 2010, 10:29:47 PM »
No,they will form a Complex Compound-Ca(NH3)4Cl2,which can dissolve in water .ZnCl2 and AgCl can also form Zn(NH3)4Cl2and Ag(NH3)4Cl,,many elements can form complex compound.

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Re: Will Calcium hydroxie form?
« Reply #2 on: October 03, 2010, 04:02:49 AM »
No,they will form a Complex Compound-Ca(NH3)4Cl2,which can dissolve in water

No such complex.
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Re: Will Calcium hydroxie form?
« Reply #3 on: October 03, 2010, 04:03:25 AM »
I was asked if NH3 solution is mixed with 0.5 CaCl2, should Ca(OH)2 form? Make a prediction based on the fact that the pH of 1 M NH3 is about 11.6? The answer is that it SHOULDN'T form, but I have NO idea why...I know Nh3 is a weak base and CaCl2 is an acidic solution, but I don't understand how I can tell whether Ca(OH)2 can form or not..

What is solubility product of Ca(OH)2?
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Offline jonjon1324

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Re: Will Calcium hydroxie form?
« Reply #4 on: October 03, 2010, 03:15:26 PM »
I was asked if NH3 solution is mixed with 0.5 CaCl2, should Ca(OH)2 form? Make a prediction based on the fact that the pH of 1 M NH3 is about 11.6? The answer is that it SHOULDN'T form, but I have NO idea why...I know Nh3 is a weak base and CaCl2 is an acidic solution, but I don't understand how I can tell whether Ca(OH)2 can form or not..

What is solubility product of Ca(OH)2?

It is 3 x 10^-5

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Re: Will Calcium hydroxie form?
« Reply #5 on: October 03, 2010, 03:23:58 PM »
My book gives different value, but let's assume the one you listed is the proper one, that you are expected to use.

Do you see why solubility product of calcium hydroxide is relevant? Can you think of a way to use it to check if calcium hydroxide will precipitate?
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Offline ooosh

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Re: Will Calcium hydroxie form?
« Reply #6 on: October 03, 2010, 11:42:28 PM »
No,they will form a Complex Compound-Ca(NH3)4Cl2,which can dissolve in water

No such complex.

sorry,CaCl2.8NH3,ok?

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Re: Will Calcium hydroxie form?
« Reply #7 on: October 04, 2010, 05:54:43 AM »
sorry,CaCl2.8NH3,ok?

No, this is an exotic compound that you will never see in water solution.
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