April 19, 2019, 05:00:31 AM
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Topic: Precipitation reaction  (Read 369 times)

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Offline kdbmvp

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Precipitation reaction
« on: February 14, 2019, 05:05:59 AM »
Hello,

I have a question regarding precipitation reactions. Consider the following rx:

Pb(NO3)2 + 2NaOH -> Pb(OH)2+ 2Na+ + 2NO3-

My question is: Why doesn't the 2Na+ cations react with the 2NO- anions, but remain spectator ions?
« Last Edit: February 14, 2019, 05:23:24 AM by kdbmvp »

Offline chenbeier

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Re: Precipitation reaction
« Reply #1 on: February 14, 2019, 05:15:18 AM »
First there will be no NO-.

If you dissolve Pb(NO3)2 and NaOH seperatly in one beaker glass then you get Pb2+ and 2 NO3- and in the other glass Na+ and OH-.

If you now mix both solution the lead hydroxide Pb(OH)2will precipitate . The Na+ and NO3- will be still dissolved in the solution. There for we call them spectator ions.

Offline kdbmvp

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Re: Precipitation reaction
« Reply #2 on: February 14, 2019, 05:23:02 AM »
Sorry about that, writing mistake. Meant NO3-. But why doesn't Na+ and NO3- react? What determines this?

Offline chenbeier

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Re: Precipitation reaction
« Reply #3 on: February 14, 2019, 05:31:52 AM »
They still swimming in the solution. Sodium nitrate is good solouble. If you evaporate the water you will get NaNO3.

I tis the same you dissolve NaCl. You get Na+ and Cl-. You get the salt back, if the water is removed.

Offline kdbmvp

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Re: Precipitation reaction
« Reply #4 on: February 14, 2019, 05:57:10 AM »
Thank you!

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