$(10$ pt$)$ Assessing the speciation of organic acids and bases in natural waters

a$)$ Calculate the fraction of $3,4-$dimethylaniline $($DMA$)$ present at $24C$ as neutral

species in a raindrop $(pH=4\mathrm{.}0)$ and in lake water $(pH=8\mathrm{.}0).$

$3,4-$DMA

$p{K}_{ia}=5\mathrm{.}28$

b$)$ Compare the result with PCP in the example $1$ of the lecture note. Which one is a

stronger acid? Discuss environmental implications.