Big-Daddy

Hi, sorry if this is a stupid mistake or I should be ignoring Wikipedia, I'd just like clarity. As I understand it, the concentration of H3O+ ions in an acidic solution is denoted by (x^3)+(Ka*(x^2))-((Kw*x)+(C*Ka*x))-(Kw*Ka)=0 (where x is the concentration of H3O+ ions, C is the starting concentration of acid molecules, Ka is the acid dissociation constant and Kw is the auto-ionization constant of water. My question is, assuming that the above is correct (if it's not please correct me), is it safe to describe the concentration of OH- ions in an alkaline solution with (x^3)+(Kb*(x^2))-((Kw*x)+(C*Kb*x))-(Kw*Kb)=0 (where x is now the concentration of OH- ions instead)? The doubt arises because Wikipedia says that "For alkaline solutions an additional term is added to the mass-balance equation for hydrogen. Since addition of hydroxide reduces the hydrogen ion concentration, and the hydroxide ion concentration is constrained by the self-ionization equilibrium to be equal to Kw/[H+]", so it appears that, in the alkaline equation, I should simply keep x=concentration of H3O+ and replace all the current 'x's with 'Kw/x' (which will thus be equal to the concentration of OH-). But I don't see why that's necessary - can't I just use (x^3)+(Kb*(x^2))-((Kw*x)+(C*Kb*x))-(Kw*Kb)=0 where x is the concentration of OH- ions for my calculation? If I want to calculate H3O+ ions additionally, can't I just use [H3O+]*[OH-]=Kw after I solve the cubic above? E.G. If I want to calculate the H3O+ ionic concentration in an alkaline solution, can't I just use (x^3)+(Kb*(x^2))-((Kw*x)+(C*Kb*x))-(Kw*Kb)=0 where x is the concentration of OH- ions and then use [H3O+]=Kw/[OH-]? If so, why does Wikipedia suggest using a Kw/[H3O+] system? If not, where am I going wrong? Thanks a lot for any help.

Hi, sorry if this is a stupid mistake or I should be ignoring Wikipedia, I'd just like clarity. As I understand it, the concentration of H3O+ ions in an acidic solution is denoted by (x^3)+(Ka*(x^2))-((Kw*x)+(C*Ka*x))-(Kw*Ka)=0 (where x is the concentration of H3O+ ions, C is the starting concentration of acid molecules, Ka is the acid dissociation constant and Kw is the auto-ionization constant of water. My question is, assuming that the above is correct (if it's not please correct me), is it safe to describe the concentration of OH- ions in an alkaline solution with (x^3)+(Kb*(x^2))-((Kw*x)+(C*Kb*x))-(Kw*Kb)=0 (where x is now the concentration of OH- ions instead)? The doubt arises because Wikipedia says that "For alkaline solutions an additional term is added to the mass-balance equation for hydrogen. Since addition of hydroxide reduces the hydrogen ion concentration, and the hydroxide ion concentration is constrained by the self-ionization equilibrium to be equal to Kw/[H+]", so it appears that, in the alkaline equation, I should simply keep x=concentration of H3O+ and replace all the current 'x's with 'Kw/x' (which will thus be equal to the concentration of OH-). But I don't see why that's necessary - can't I just use (x^3)+(Kb*(x^2))-((Kw*x)+(C*Kb*x))-(Kw*Kb)=0 where x is the concentration of OH- ions for my calculation? If I want to calculate H3O+ ions additionally, can't I just use [H3O+]*[OH-]=Kw after I solve the cubic above? E.G. If I want to calculate the H3O+ ionic concentration in an alkaline solution, can't I just use (x^3)+(Kb*(x^2))-((Kw*x)+(C*Kb*x))-(Kw*Kb)=0 where x is the concentration of OH- ions and then use [H3O+]=Kw/[OH-]? If so, why does Wikipedia suggest using a Kw/[H3O+] system? If not, where am I going wrong? Thanks a lot for any help.

Well, let's answer the basic question first. H+ ions (meaning, I think, H3O+ ions) - would a beaker of them be that acidic? It looks to me like the maths breaks down here - [H3O+]=Kw/[OH-], and if there isn't a single OH- ion, our H3O+ concentration will be infinite, which obviously doesn't work. I don't know what the properties will be like. Maybe someone else can clarify? As for the "strongest acid" question, a good scale to use would be the pKa scale, by which the strongest acid is fluoroantimonic acid (HF-SbF5), basically a H+ ion loosely attracted to one of 6 F- atoms held in covalent single bonds with an antimony atom). This is a superacid that far exceeds any other, with a pKa of -25. HClO4 (the strongest typical acid) has a pKa of only -8 and sulphuric acid has one of -3.3. This means that fluoroantimonic acid is basically 10^21 times stronger than H2SO4 (I'm not even joking). For some pH examples, 1M of H2SO4 has a pH of 0; 1M of HClO4 has a pH of 3.24*10-9; and 1M of HF-SbF5 has a pH of below -20. And the pH scale is logarithmic.