Answer
See the answer below.
Work Step by Step
a) Water exhibits hydrogen bonding and therefore has stronger intermolecular forces than $H_2S$.
b) $P=80/1000000×725\ mmHg=0.058\ mmHg$
c) At the same Temperature and Pressure, $V\propto n$, and the ratio of the volumes is the stoichiometric ratio: 10.4 L.
