# What is the molar concentration of H3O+ in a cola that has a pH of 3.120?

$\text{pH}$ is the inverse logarithm of the concentration of hydronium ions in solution. It determines the acidity of solution. Likewise, its antilog will give the concentration of hydronium ions,
$\left[{H}_{3} {O}^{+}\right] = {10}^{- 3.120} \approx 7.586 \cdot {10}^{-} 4 M$