Need source for bulk quanities of NaHO

[Casey]

I live in the northwest corner of California's share of the Great Mojave Desert. Just about 160 miles due north of Los Angeles. To give you an idea of remoteness, the nearest shopping mall is a 75-mile drive.

Anybody know a source for bulk NaHO 0.2N solution without having to pay double or triple for shipping costs? The typical 4 ounce bottle for a titration kit is good for 6 maybe 7 tests -- 8 at the most. With a liter I could get 70 or 80 tests.

 

[Manimal]

Any supplier of chemicals should be able to get you pure, granular NaOH. It has a molecular weight of 40 grams/mole... so you can make up your own 0.2N solution using 8g of NaOH and adding enough distilled water to bring up the volume to 1 liter. In practice, it would probably be better to make it up in smaller quantities, like 500 or 250ml and adjusting the calculations accordingly. You will need an accurate balance that reads into the tenths/hundreds of a gram and an accurate way of measuring the volume of water such as a graduated cylinder or volumetric flask. You can also test the normality of your solution by making up a standard acid solution with a known TA and then titrating with your NaOH solution to see how close you come. I forget the exact formula off hand, but if you're interested, I can check my notes for you... I think it is:
(ml NaOH used X normality of solution X 75) / sample size (25ml) =TA

 

[Hillbilly Bill]

Manimal,
Could KOH be used in place of NaOH? I have a 1 lb. container of KOH I used to adjust pH when I grew tomatoes hydroponically. I do not have a TA kit, but am thinking of making one up using some of my old chemistry equipment, but I might need to buy a kit to help calibrate the new kit. What do you think?

 

[surlees]

Casey,

Here's a source for 10% NaOH (at bottom of page):

http://www.piwine.com/store/home.php?cat=266

To make 250 ml. of .2N NaOH, you use 18 ml. of this solution and add 232ml. of distilled water. Don't mix more solution than you will use in a couple of months and keep all NaOH solutions refrigerated to increase longevity.

Hope this helps.

Fred