A question on hydrofluoric acid...

[Alarium]

I've been assigned for a school thing to find out what hydrofluoric acid can be contained in and why. I've found that it can be contained in polyethylene containers, now I just need to find why. I haven't been able to do so yet. Does anyone know the reason for this?

 

Also, it can't be contained in glass containers because it is one of the things used to etch glass, I need to know why this is as well.

[YT2095]

have a good read about "electro Negativity"

 

Lithium Hydroxide will also attack glass, but that`s at the opposite end of the "electro-Negativity" scale!

 

Flourine will also react quite effectively with Xenon, a group 8 element considered INERT! ( it`s a nobel gas)

 

Flourine it THE MOST electro-Negative element known

 

(it`s pretty darn poisonous too, so be carefull if you have to do a practical test with it, although PURE HF will not attack glass, it needs the water (OH ions) to "activate")

 

hope this helps a little

 

 

[Alarium]

Well, thanks for that. I'll check into it.

 

I did find out from the teacher who gave me the assignment basically why it eats through the glass. What he said is that it basically does something to disloge the oxygen in the glass (made of silicon di-oxide), thus eating through the glass.

 

And I from reading about flourine I've found that I don't think I ever want to use it. Too dangerous with fumes, strenth etc. The strongest acid I've ever had to use was an 18m sulfuric acid. It was being used as a catalyst in making esters.

[T_FLeX]

I think it can be held in platinum also, but that might put a huge dent in your wallet.

 

Is hydrofluoric acid similiar to hydrochloric acid? In that it is extremely soluble in water, and just basically hydrogen fluoride gas dissolved in water?

[YT2095]

it isn`t quite as soluable in water as HCl is, nor as volatile in terms of temperature decomposition, but basicly yes, it is the gas HF dissolved in water.

[Alarium]

Well Fluorine, and Chlorine are both members of group 17 on the periodic table. Fluorine is the most reactive of the non-metals, and chlorine is close behind.

 

If you were to put fluorine in a container with HCl a single displacement reaction would occur, causing the Chlorine leave as a gas again.

[YT2095]

Chlorine is also quite a reactive Oxidiser indeed

after Fluorine though would be Ozone O3 as the next most reactive (electro negative).

 

 

 

(btw, it`s a group 7 element not 17 ya made a simple typo, I`ll remove this when you correct it, cheerz )