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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Tom on June 03, 2004, 04:28:19 PM

Title: Precipatation of BaCO3
Post by: Tom on June 03, 2004, 04:28:19 PM

If a solution contains Ba+2 and Mg+2 each at a concentration of 1.0 x 10-3 M at 25º C.  Predict what will happen if the carbonate ion concentration is made 0.001 M (KspBaCO3= 8.1 x 10-9, Ksp MgCO3 = 4.0 x 10-5).

Would both MgCO3 and BaCO3 precipitate or neither will precipitate?

Title: Re:T/F Questions
Post by: Donaldson Tan on June 03, 2004, 09:17:56 PM

Tom: you can use the supscript (sup) and subscript(sub) button fyi.

Usually, the salt with the lower solubility product constant will precipitate preferentially.

Ba²⁺(aq) + CO₃^2-(aq) <-> BaCO₃(s)
Mg²⁺(aq) + CO₃^2-(aq) <-> MgCO₃(s)

when [ CO₃^2- ] = 0.001,
Ionic Product for MgCO₃
= (1.0X10^-3)(0.001)
= 1.0X10^-6 (< Ksp)
Ionic Product for BaCO₃
= (1.0X10^-3)(0.001)
= 1.0X10^-6 (< Ksp)

Since in both cases, the respective ionic products are less than their respective Ksp, precipitation of neither carbonate occurs.

Title: Re:Precipatation
Post by: Tom on June 04, 2004, 09:19:02 AM

Thankyou for explaining that Mana.

I appreciate it.

Tom