The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Is this titration procedure correct?

September 5, 2008

Is this titration procedure for Total sulfuric acid correct? (we are using 66° sulfuric acid)

pipette [pipettes on eBay or Amazon [affil links] a 2 ml sample into flask
dilute to 100 mls with DI water
add 3 drops of Phenolphtalein indicator
Titrate with 1.0N Sodium Hydroxide to a pink endpoint
mls titrated x 3.28 = oz/gal

For creating a new bath is this correct?

Multiply tank size (gallons) x percent H2SO4 needed x .625 = gallons of 66° needed

Thanks,

Mike Davis
shop employee / hobbyist - Kalispell, MT, USA

---

September 8, 2008

Sir:
The answer to your question is: NO

Dr. Thomas H. Cook
Galvanizing Consultant - Hot Springs, South Dakota, USA

---

September 10, 2008

Mike

To me, your calculations to get oz/gal look correct. Now, when calculating how much to add:

Find the number of additional ounces of sulfuric needed and then divide by 235 which is the reagent strength in oz/gal of 66 baumé sulfuric acid.

example:

10 oz/gal x 100 gal tank = 1000 oz current
say you want 20 oz/gal x 100 gal = 2000 oz
so need additional 1000 oz
1000 oz / 235 = 4.25 gallons needed

make sure before you make an add that your tank has enough space in it without overflow

The above example only applies to a 100 gallon tank using 66 baumé sulfuric acid.

Terry

Terry Tomt
- Auburn, Washington

Terry, Thanks for the info

Mike Davis
- Kalispell, MT, USA
September 24, 2008