If you have not done so, please read the "DOs and DON'Ts section now".

Equipment Required:

• Titration flask (125 ml)
• 10 ml Automatic pipettor
• Digital titrator

Reagents Required:

• Deionized water
• Bromphenol blue indicator
• 1.60N Sodium hydroxide (titrant)

Procedure:

1. Measure 30 ml of deionized water into the titration flask. (Quantity is not critical)
2. Using the automatic pipette, add .10 ml of sample solution.
3. Add one drop of bromphenol blue indicator to the flask. Swirl the flask around to mix thoroughly. The solution will turn a light yellow color with the addition of the indicator.
4. Using the digital titrator, titrate with 1.60N sodium hydroxide until the solution turns light blue. Record the number of drops of titrant used as indicated on the digital readout.
5. The amount of sulfuric acid that is needed for a bath with volume=V (liters) can be calculated using the relationship below (the digital titrator reading is denoted NumSulf).

If 35% sulfuric acid (automotive battery grade) is used to increase the acid content, use:

Liters of H2SO4 needed = [0.10 - (0.000535 x NumSulf)] x V / 0.35

If 98% sulfuric acid (concentrated plating grade) is used to increase the acid content, use:

Liters of H2SO4 needed = [0.10 - (0.000535 x NumSulf)] x V / 0.98

To express the concentration of sulfuric acid as a percent of bath volume, use:

% H2SO4 = 0.0535 x NumSulf

The acceptable range of NumSulf is:

Optimum Range: 8 to 10%

NumSulf: 150 to 187

CAUTION:

Always use the proper attire as outlined above in the SAFETY section when handling concentrated sulfuric acid. If contact should occur, flush affected area with cool tap water for 15 minutes. CONTACT A PHYSICIAN IMMEDIATELY.

HANDLE WITH CARE:

Always wear protective clothing, acid resistant gloves, and a full coverage face shield when handling this or any other corrosive material.