Mr. Jeffy32 please help me out with understanding how alkaline-forming (al-f) mineral increase pH?

Question

As you no doubt know I've been having trouble finding an answer to this question. Since potassium is highly concentrated in cells, and the cell is 70% water, the form of potassium in food should be ionic potassium (K+). When you eat food the cells of the food go through digestion releasing the potassium ions. Even if we assume al-f minerals are mineral salts or chelate form, the al-f minerals would detach and pH coincidentally or not coincidentally would still increase. Al-f minerals are called al-f minerals becuase they increase pH. What do al-f minerals do in the body that causes pH to increase? KOH does not increase pH as you and other have explained. Please explain only in terms of human body chemistry. If yahoo answers format limits your answer, write me at [e-mail]

Answer 1

You are wondering how certain compounds (in particular, Potassium compounds) can change/increase the pH of a solution.
If you want to increase the pH of a solution you need to do one of two things…either increase the concentration of Hydroxide ions (OH-), or decrease the concentration of Hydronium ions (H+, or, H3O+). When [H+] = [OH-], the pH is neutral, but if [OH-] > [H+], the pH is alkaline (pH > 7).

How can a Potassium compound (“salt”, in the general sense of the term) increase the pH then? Well, it could do one of the two methods listed above.

There is a special type of Potassium Salt which is known as Potassium Hydroxide (KOH). Potassium Hydroxide is a strong electrolyte, meaning that when you dissolve it in water it will completely disassociate into ions. Furthermore, KOH is a strong base in that not only will it completely disassociate into ions, but by doing so it will increase the concentration of Hydroxide ions, [OH-], in solution. By dissolving KOH in water, the pH of the resulting solution will be greater than 7 (alkaline). (I think you may have misunderstood what I said earlier about this.)
So with this method, you are directly increasing the Hydroxide ion concentration in the water by adding more OH- ions, which results in a higher pH.

There are other types of Potassium salts, one’s with anions (-) that are said to be the conjugate base of a weak acid. For example, Potassium Bicarbonate (KHCO3) has a HCO3- anion which is the conjugate base of the weak acid known as “Carbonic acid” (H2CO3). Carbonic acid is a weak acid because (unlike strong electrolytes/acids) it does not readily split up into ions in solution…it will mostly stay as H2CO3 and not beak up into H+ and HCO3-.
When you dissolve Potassium Bicarbonate in water, it breaks up into Potassium ions (K+) and Bicarbonate ions (HCO3-). At the same time, remember, the water itself is breaking up (slightly) into H+ and OH- ions. So now you have a mix of K+, HCO3-, H+, and OH- ions in solution. Originally, the water’s H+ and OH- ions are in equal amounts and the pH is neutral, but then you come along and add the K+ and HCO3- ions to the solution. Remember what I said about Carbonic acid not breaking up into ions very readily….well in a way that is just what you forced it to do (kind of, if that is how you want to think of it). Those H+ ions and HCO3- ions “see” each other and know that there should not be this many free, disassociated ions, and start to combine. A certain amount (not all, but most) of H+ and HCO3- ions combine to form the undissassociated H2CO3. Since only free H+ ions can affect the pH of the solution…the solution’s pH will rise now that the H+ concentration has gone down. Some of the H+ ions that were originally in balance with the water’s OH- ions have been “robbed” by the Bicarbonate ions to form a weak, undissassociated, acid.
The same process does not occur with the Potassium ion. If the K+ were to combine with one of the water’s free OH- ions, it would form the strong base Potassium Hydroxide. But, as described above, Potassium Hydroxide is a strong base and would immediately disassociate again into ions so that no net reaction would occur.
As a result of this, there are now more free OH- ions than free H+ ions and the pH increases.

Now all Potassium salts will affect the pH of the solution however. Some salts’ ions are the conjugate acids/bases of other strong acid/bases and will thus stay disassociated into ions when they come in contact with water’s H+ or OH- ions.
For example, Potassium Chloride will not affect the pH of a solution when dissolved in water since the only two other products it could form would be KOH and HCl, which would then just cancel each other out again and re-disassociate.

These examples above are not only true for Potassium; they will also work for other cations with similar properties (like Sodium, for example).


* Remember, what I am saying above is for a general solution, not necessarily for bodily fluids or solutions inside cells. When considering these, certain practical conditions must be accounted for…for example, the fast that when you eat something the food passes through the highly acidic stomach which would tend to neutralize any bases added directly to the body (if one was to, for example, just eat a bunch of KOH).

Answer 2

I've been vegetarian for nearly 14 years and have had NO health problems associated with it. There are extremists who say a vegetarian diet is awful and ones who say it will cure everything. Neither is true. A well balanced vegetarian diet meets all the same nutritional requirements as a diet with meat. Your teacher has no idea what he's talking about. He may just be another guilty omnivore who is looking for any justification to continue his meat eating lifestyle.