Question

Cola drinks have a phosphoric acid content that is described as "from 0.057 to 0.084% of 75% phosphoric acid, by mass."

Estimate the pH range of cola drinks corresponding to this range of H3PO4 content.

pH range lower limit:

pH range upper limit:

Answer 1

For the lower limit I would multiply 0.00057*75 which gives g/100 and multiply by 10 to convert to g/L. Then g/molar mass H3PO4 = moles/L = M
Look up k1 for H3PO4, solve for H^+ and convert to pH.
The upper limit would be similar.

Answer 2

2.33*10^-3