Answer
$CH_3SH$ is more acidic.
Work Step by Step
- In the first compound $(CH_3SH)$, the conjugate base will have a Sulfide with the negative charge.
- In the second compound $(CH_3OH)$, the conjugate base will have a Oxygen with the negative charge.
Since they are in the same column, we need to compare their sizes:
- $S$ is bigger than $O$, so the charge is better stabilized on the $S^-$.
- Therefore, $CH_3SH$ is more acidic.
