# Isolation of salt from solution

I just want to clarify my understanding of whether metathesis can be used to form other products by combining an acid and a base (do special rules apply whether its strong/weak acid/base)?

Say I want to form some $\ce{Na2CrO4}$. There's many ways to do this but the most obvious one I can think of is:

$$\ce{2NaOH(aq) + H2CrO4(aq) ->Na2CrO4(aq) + 2H2O}$$

Can you then just filter out the $\ce{H2O}$ to get your desired product? How would you do so? I'm used to looking at these in terms of net ionic equations where two aqueous reactants for a solid precipitate but since everything here would cancel out (except water) is this even a viable possibility?

• That's going to be difficult since $\ce{CrO4^{2-}}$ does not have a charge of -1. Other than that, you're basically talking about evaporating the solvent, which is definitely a thing you can do. Ideally, it's not water, because evaporating water is a pain. Though lyophilization might work. – Zhe Oct 25 '17 at 15:50
• As Zhe pointed out, you'd need to evaporate not filter the water out. But I'd agree that this is a metathesis reaction since you could isolate the two different compounds by physical means. // Evaporation with heat is a messy process since as the liquid surface disappears the solid starts to splatter. – MaxW Oct 25 '17 at 20:47
• This is not what I thought when I read ‘metathesis’ … – Jan Oct 26 '17 at 4:51