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Topic: Ionic strenght Na2SO4  (Read 1054 times)

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Offline xshadow

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Ionic strenght Na2SO4
« on: January 27, 2019, 04:30:31 AM »
HI, I know the ionic strenght of Na2SO4 0.0250M is:
μ= 1/2*(0.0500*(+1)2 + 0.0250*(-2)2)= 0.0750

But this if I put [SO42-]=2* CNa2SO4 (no hydrolysis)

But can occur the reaction :
SO42-+ H2O <------> HSO4- + OH-   pkb


Now  what's the μ expression when I consider the partial dissociation?
Perhaps
μ=1/2*(0.0500*(+1)2 + 0.0250*(-2) 2SO42- + 0.0250* (-1)2HSO4-)
???

Thanks

Offline Borek

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Re: Ionic strenght Na2SO4
« Reply #1 on: January 27, 2019, 12:43:28 PM »
You need to find the equilibrium concentrations of all ions involved and use them to calculate ionic strength. It will change the equilibrium so you should then recalculate everything. Typically 2-3 iterations are enough.
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