Question

What is the effective h3o+ concentration in a 10 mm phosphate buffer at ph 4.0?

Answer 1

The effective concentration of hydroxonium ion also known as hydronium ion, H₃O⁺ is 10⁻⁴ M.

Calculation of the concentration of a given solution be it acid or a base follow the same principle.

We know that pH is given as -log [concentration]

And for this case the pH of hydronium ion is given as 4.0.

Therefore the Concentration of hydronium ion is 10^⁻pH

i.e 10⁻⁴ which gives 1.0 x 10⁻⁴which is the same as 10⁻⁴