# Given 1*mol*L^-1 concentrations of "hydrochloric, acetic, and formic acids" in water, can you rank the solutions in order of INCREASING pH?

$p H = - {\log}_{10} \left[{H}_{3} {O}^{+}\right]$; $p H$ follows the order $H C l$ $<$ $H C {O}_{2} H$ $<$ ${H}_{3} C - C {O}_{2} H$ with respect to $1$ $m o l \cdot {L}^{-} 1$ concentrations of these acids.
And thus the STRONGEST acid will generate the LOWEST, i.e. the most negative $p H$. The given order is wrong.
$H C l$ completely dissociates to give $p H = - 1$. Formic acid should be a stronger acid than acetic acid, and will thus have a more negative $p H$; you will look up the $p {K}_{a}$ values to verify what I say.