H2SO4 - Convert from percent to pH

Standard, unbuffered aqueous solution of Sulfuric Acid with a pH of 2. How many ppm?

[JohnS]

Originally Posted by Unregistered

Standard, unbuffered aqueous solution of Sulfuric Acid with a pH of 2. How many ppm?

A pH of 2 represents a H+ concentration of 0.01 Molar (moles per liter). As H2SO4 (fully ionized) contributes 2 H+ ions, 0.005 mol/L of H2S04. The molar mass is 98.1 g/mol, so 0.49 g/L of H2SO4.

What kind of ppm would you like? The mixture is dilute and 1 L is about 1 kg so either 490 mg/kg or 490 mg/L are good approximations, so 490 ppm on either w/w or w/v basis.

Computing it on a volume ratio or molar ratio would be more complex. However, it is approximately 266 µL/L or 90 µmol/mol, which are also "ppm."