# The pH of lemon juice at 298 K is found to be 2.32. What is the concentration of H_3O^+ ions in the solution?

pH$= - {\log}_{10} \left[{H}^{+}\right]$
$\therefore$2.32$= - {\log}_{10} \left[{H}^{+}\right]$
$\left[{H}^{+}\right] = {10}^{-} 2.32$=$4.78 \cdot {10}^{-} 2$