[Leonardoanatomy]

Why is a reaction between H₂C₂O₄ and CaCl₂ a precipitation reaction?

[mkurek]

a precipitation reaction is where a reaction occurs in a solution, and a solid is formed. So if the reaction above is a precipitation reaction, that means that one of the products formed is a solid.

[Leonardoanatomy]

thnx

but do you know how I can see that this a precpitaion reaction? Do I have to write out the equations?

[Rutherford]

Yes, and you must know whether at least one of the products is insoluble in the solvent. Many factors determine this and it would be hard to memorize separately for each compound whether it is soluble or not, therefore solubility rules should be memorized: http://www.iun.edu/~cpanhd/C101webnotes/chemical%20reactions/solubilityrules.html (for aqueous solutions). Exceptions exist, e.g. LiF is insoluble, but AgF is soluble. It's all about experience.

[Leonardoanatomy]

Yes, and you must know whether at least one of the products is insoluble in the solvent. Many factors determine this and it would be hard to memorize separately for each compound whether it is soluble or not, therefore solubility rules should be memorized: http://www.iun.edu/~cpanhd/C101webnotes/chemical%20reactions/solubilityrules.html (for aqueous solutions). Exceptions exist, e.g. LiF is insoluble, but AgF is soluble. It's all about experience.

Thanks a lot! I understand!