acidic

[baedero1]

why are FeCl3 and AlCl3 acidic when dissoved in water?
thanks

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[lphiewok]

FeCl3 -> Fe (3+) + 3 Cl (-)
and I am thinking Chlorine ion will bond with Hydrogen in water and form HCl

and HCl is an aqeous acidic solution.

 

[DCRedskinsRule]

FeCl3 -> Fe (3+) + 3 Cl (-)
and I am thinking Chlorine ion will bond with Hydrogen in water and form HCl

and HCl is an aqeous acidic solution.

But acidity just had to do with [H] and whether or not the Cl is in solution and "forms HCl" has nothing to do with it because the [H] is still just coming from water.

IMO, and I'm not 100% sure but I think this is right, it actually has to do with the [OH]. When you put FeCl3 in water, it ionizes (I think) so there is Fe3+ and Al3+ floating around in solution. But Fe(OH)3 from what I remember (and Al(OH)3 are both pretty insoluble, and I think they would precipitate out of solution. If that's true, then there is a lower [OH] to serve as a buffer for the [H] in solution, so there's a greater ratio of [H] than [OH] so it's more acidic.

Again, that's my opinion. I'm not 100% by any means, so someone check me on this.

 

[osimsDDS]

But acidity just had to do with [H] and whether or not the Cl is in solution and "forms HCl" has nothing to do with it because the [H] is still just coming from water.

IMO, and I'm not 100% sure but I think this is right, it actually has to do with the [OH]. When you put FeCl3 in water, it ionizes (I think) so there is Fe3+ and Al3+ floating around in solution. But Fe(OH)3 from what I remember (and Al(OH)3 are both pretty insoluble, and I think they would precipitate out of solution. If that's true, then there is a lower [OH] to serve as a buffer for the [H] in solution, so there's a greater ratio of [H] than [OH] so it's more acidic.

Again, that's my opinion. I'm not 100% by any means, so someone check me on this.

Yea nice this is true...FeCl3 does react with water to form Fe(OH)3 which is not soluble so it precipitates therefore no OH- (base) will be in solution, rather H+ ions left over from the water will be in solution making it acidic...this is actually a very good problem thanks for bringing it up...