Neutralizing pH

[Mercedes Benzene]

The problem is that I can't test the pH before I neutralize it. I don't know weather it is acidic or basic. I also don't know what I am going to be neutralizing all I know is that it is water with either an acid or a base added to it.

Use some sort of acid base indicator. Phenolphthalein is one of my favorites, but many indicators exist. Once you add the indicator, you can add either the acid or base until the color changes, indicating neutrality or the inverse acid/base ion concentration. You can keep adjusting the sample until you achieve the desired pH (which in your case I guess would be 7). It sounds like a buffer solution is what you need. I suggest dibasic potassium phosphate. That's a good all-purpose buffer.

[Michaelangelica]

Originally Posted by Mercedes Benzene

I suggest dibasic potassium phosphate. That's a good all-purpose buffer.

I have some soil with a ph of 9 !!
What would you suggest here?
I have used some sulphur so far.

[Mercedes Benzene]

Well, if it's soil with a pH of 9, I would use a buffer solution of citric acid and some sort of weak conjugate base, both of which can probably found at a store near you. You could also try acetic acid (which is not a buffer by the way) which can be bought as a dilute solution in vinegar.
Use litmus to test for the neutrality of the soil after attempting to change its pH.
Let me add that if you want to create your own buffer, it should consist of an acid and its conjugate base.
GOOD LUCK! and have fun!

[hallenrm]

Originally Posted by sciguy1216

The problem is that I can't test the pH before I neutralize it. I don't know weather it is acidic or basic. I also don't know what I am going to be neutralizing all I know is that it is water with either an acid or a base added to it.

Well there are indicators to tell you whether the substance you want to test for acidity or alkalinity. You can use turmeric, it turns pink with alkaline substances. Then there are flower pigments too!

The best of course is to use phenolpthalein or metyl orange soltion if you can get hold of them You can perhaps find them from the chem lab. of a neighboring school.

Happy neutralizing sciguy

[Michaelangelica]

Originally Posted by hallenrm

Well there are indicators to tell you whether the substance you want to test for acidity or alkalinity. You can use turmeric, it turns pink with alkaline substances.

That's fascinating Thanks
I know about hydrangea flowers going pink (Acid?) and Blue (Alkaline?) but don't know of other flowers. Do tell.

To get completely off the topic; apparently some plants have an affinity for metals like gold, silver, copper iron-ore in the soil. When you see these plants you call in the geologists -or not, if its gold. Don't know what the plants are though.)

Originally Posted by hallenrm

The best of course is to use phenolpthalein or metyl orange soltion if you can get hold of them

I use a soil test kit developed by the CSIRO that's why I know the Ph is nine.(One of the chemicals in it is a dark orengy red colour -liquid)
I think the person who started this thread can't test the soil first for some unknown reason.
--
Michael

[hallenrm]

Originally Posted by sciguy1216

I was wondering if anyone knew if there was a chemical that could neutralize pH. I can't test the pH before changing it so it needs to be able to raise OR lower pH.

Thanks,
sciguy

Well, the chemicals used for finding out the approximate pH of a substance are called acid base indicators. These substances need not neccesarily be bought you can get them from the flowers and vegetables around you.

You really need not worry very much of the change in pH while measuring it. pH doesn't change appreciably unless one adds a strong acid ( say hydrochoric acid) or a strong base to it. Indicators are invariably very weak acids and bases.

If your interest in the acids and bases is because of the alkaline nature of the soil in your garden, you can use any acidic waste products prome your kitchen or neighborhood. the rind of most citrus fruits (oranges, lemon etc) is acidic.

[Michaelangelica]

Still battling my soil problem
This is an important thread for the new Ag /Hort Sci. Forum.

[HydrogenBond]

An interesting plant is the hydrangea. It is a natural pH meter, with the flowers of some versions turning either blue or pink depending on the pH of the soil. The color shift has to do with the aluminum in the soil, which is more available to the plant at lower pH. At higher pH less aluminum is soluble so the color changes.

[UncleAl]

Add glycine. Acid will protonate the carboxyl, base will deprotonate the ammonum. Glycine buffers pH 6, Good buffer BES 7.2, molar 1:1 Na2HPO4, NaH2PO4 pH 7.5. Glycine's low molecular weight is its advantage.


The perfect answer is to run the solution through consecutive beds of strong cation (as free acid) and strong anion (as hydroxide base) hydrated beaded gel ion exchangers. Neutral deionized water comes out the bottom - except for dissolved carbon dioxide. Vacuum degas.

[maikeru]

Originally Posted by Michaelangelica

Still battling my soil problem
This is an important thread for the new Ag /Hort Sci. Forum.

Have you amended the soil with a lot of compost, wood chips or sawdust, or bark? Organic matter should help bring down and stabilize the pH more. I think compost usually has a pH around 6.5-7-ish or so. As wood chips or sawdust decompose they should lower pH as well. Many kinds of bark are rich in tannins which tend to be more acidic. Be aware that the addition of wood chips, sawdust, or bark to the soil may create a short-term nitrogen deficit and hurt plant growth (although it should correct itself with time, as the microbes die and release it back into the soil).