What is the PH range between 58 grams and 87 grams of Sodium Hydroxide in 6 oz by volume of water. What is the PH range of that amount of Sodium Hydroxide in 8 oz of water. I need this information to learn to make soap using wood ash.

Is that 6 fluid ounces or 6 ounces dry measure?. The measure is slightly different but I don't think that will make any difference in soap making. 1 ounce (mass) = 28.35 grams; therefore, 6 ounces = 170 grams and 8 oz = 227 grams.

I should point out that if you are making it with wood ash, you will be using KOH and not NaOH.
moles NaOH = 58/40 = 1.45.
Assuming that adding NaOH to 170 mL water doesn't change the volume of the water (not exactly a good assumption), then
M NaOH = 1.45/0.170 = 8.5 M OH^- which gives you a crazy number like -0.93 for pOH and 14.93 for pH (remember the scale only goes to 14). None of that really makes sense anyway because in a concd solution such as that the pH doesn't mean very much. Remember, too, that if you are using wood ash for the KOH, that will not be pure KOH. Technically, it is K2O (and only a small percentage at that) in the wood ash and becomes KOH when dissolved in water.
87/40 = 2.17 moles and
2.17/0.170 = 12.8M for OH^- and the pH =15.1.
If you want to recalculate for KOH, use 56 for the molar mass KOH instead of 40 for NaOH.
Follow the above for the 8 oz (227 grams). The numbers won't be that different.

I know how to make soap, using lye. I want to be able to make the lye solution from wood ash be the same ph as commercial lye. I think this can be done using the ph of sodium hydroxide in water as I first stated. Is it possible to compute this ph.

I need to duplicate the strength of lye made from wood ash dissolved in water (Potassium Hydroxide) to that of lye made from Sodium Hydroxide disolved in water. The soap recipes I use require lye of various strengths as determined by fluid volume of water combined with the prescribed humber of grams of sodium hydroxide. e.g. 6 fluid oz of water combined with 58 g of sodium hydroxide. This makes lye of a specific strength. I want to be able to duplicate the strength of the sodium hydroxide lye water when useing potassium hydroxide made from dissolving wood ash in water. I can make the potassium hydroxide lye water stronger by reducing its volume with heat or weaker by increasing its volume by adding more water. I assume the easiest way to make potassium hydroxide lye water of the same strength as the sodium hydroxide lye water is to make them have the same PH. To do this I need to know the PH of a solution made from 6 fluid oz of water combined with 58 gr of sodium hydroxide.

To determine the pH range of a solution, you need to check the concentration of the substance and its pKa value, which indicates the strength of its acidity or alkalinity. Unfortunately, the information you provided is not sufficient to calculate the pH range.

Additionally, making soap using wood ash is a slightly different process compared to using sodium hydroxide. Wood ash contains potassium hydroxide, which produces a different type of soap called "soft soap."

If you are interested in making soap using sodium hydroxide, here's a general guideline:

1. Calculate the amount of sodium hydroxide needed:
- Determine the desired amount of soap.
- Use a soap calculator to calculate the exact amount of sodium hydroxide needed based on the oils and fats you plan to use in your soap recipe.

2. Prepare the solution:
- Measure the weight of sodium hydroxide required based on the soap calculator's recommendations.
- Use protective gloves and goggles to handle sodium hydroxide. Be cautious as it is highly caustic.
- Slowly add the required amount of sodium hydroxide to a container with a suitable amount of water, stirring continuously until it dissolves completely. (Remember, always add sodium hydroxide to water, not the opposite.)

3. Check the pH level:
- Use pH strips or a pH meter to measure the pH of your soap mixture.
- Typically, the pH range of soap made with sodium hydroxide is around 9-10, which is mildly alkaline.

It is important to note that when working with lye (sodium hydroxide), proper safety precautions should be followed. Always wear protective gear (gloves, goggles, and a mask) and work in a well-ventilated area.