Understanding the Relationship

* pH is a measure of the acidity or alkalinity of a solution. It's defined as the negative logarithm (base 10) of the hydronium ion concentration ([H3O+]).

* [H3O+] represents the concentration of hydronium ions (H3O+) in moles per liter (mol/L).

The Formula

The relationship between pH and [H3O+] is:

pH = -log[H3O+]

To solve for [H3O+], we need to rearrange the formula:

[H3O+] = 10^-pH

Calculation

1. Substitute the given pH value:

[H3O+] = 10^-2.34

2. Calculate using a calculator:

[H3O+] ≈ 4.57 x 10^-3 mol/L

Therefore, the H3O+ concentration in a solution with a pH of 2.34 is approximately 4.57 x 10^-3 mol/L.