[Diamonds]

Hello,

For a reaction I saw on a test, it said

3HF + Al(OH)₃  3H2O + Al³⁺ + 3F^-

However, fluorides are typically insoluble and AlF₃ is at around 0.2g / 100 g H₂O. So why is it written this way, as if they were separate, and not as a molecule of AlF₃?

[Borek]

So why is it written this way

Because whoever wrote it concentrated on the neutralization reaction and forgot/was not aware of the low AlF₃ solubility.

I must admit I didn't know AlF₃ is that insoluble.

[Diamonds]

But this is the National Chemistry Olympiad who wrote this as the correct answer - they wrote it ionized, not as precipitated. Is that just a mistake on their part then?

[Borek]

That would be my understanding.