[idieh]

Hello,

firstly i have to admit that my "science english" is not the best, 'cause I'm from a non-English country. So i have nothing against correcting it if you want to do so.

1. I have to draw the Lewis Formula of Borax, due to which I have to determine which way of writing down the molecular formula is the best.
a) Na₂B₄O₇ * 10 H₂O or b) Na₂O₃ * 2 B₂O₃ * 10 H₂O or c) Na₂[B₄O₅(OH)₄] * 8 H₂O

Of course I have an own guess, but I'm not sure:



Well, i think this should be the "[B₄O₅(OH)₄]^2-" part, just forgot the 2 Na⁺ ions, which are according to my inorganic book coordinated by 4 H₂O molecules per Na⁺-ion.

So, my guess is, that answer c) is right, because those Hydroxyl groups of the hydroxoborate-anion shouldn't be counted in as H₂O molecules. Pls correct me if I'm wrong.

2. Borax can be used as a detection method for metal cations. I have to write down the equation for Na₂B₄O₇ * 10 H₂O + MnSO₄   Metaborate + ?

I don't have any clue for this
edit:/ spontaneous idea: Na₂B₄O₇ * 10 H₂O + MnSO₄ -->2 NaBO₂ + Mn(BO₂)₂ + SO₃ + 10 H₂O (g)

So, pls help me

[darko]

1) yes, c is correct answer, and the sketch of structural formula is ok
2)?