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Topic: Why does cyanide salts are used in acid pH?  (Read 2674 times)

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Offline arkantos

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Why does cyanide salts are used in acid pH?
« on: August 11, 2013, 09:50:05 PM »
I am trying to understand why higher concentrations of H+ speeds up cyanide action.
As far as I know, what kills the individual is the cyanide anion (CN-), not the cyanide acid (HCN).

Let's say we have a cyanide salt dissolved in a glass of water and then we add an acid (or we can imagine an empty stomach that is extra acidified):

1-) KCN(aq)  :rarrow: K+(aq) + CN-(aq)
2-) CN-(aq) + H2O(l) :lequil: HCN(aq) + OH-(aq) (hydrolysis)
3-) OH-(aq) + H+(aq) :rarrow: H2O(l)
Global process: KCN(aq) + H+(aq) :rarrow: HCN(aq) + K+(aq)

As we can see, the addition of ions H+ reduces the ammount of ions CN- and favours the formation of HCN. What I am missing?

Another ilustration: In gas chambers, one makes the following reaction, to produce HCN(g):
H2SO4 + 2KCN  :rarrow: 2HCN + K2SO4

Why not ingest KCN(aq)?

Obs1: Sorry for my english
Obs2: I am not trying to kill anyone, just trying to understand the process.
« Last Edit: August 11, 2013, 10:14:37 PM by arkantos »

Offline arkantos

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Re: Why does cyanide salts are used in acid pH?
« Reply #1 on: August 11, 2013, 09:55:29 PM »
sorry. Some issues while editing the post

Offline Archer

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Re: Why does cyanide salts are used in acid pH?
« Reply #2 on: August 12, 2013, 01:07:01 AM »
What is the mechanism of cyanide toxicity?

How would CN- get to the site where this mechanism takes place?
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