Answer
See the answer below.
Work Step by Step
Freezing point and vapor pressure depression and boiling point elevation are proportional to $i.m$, and for the ionic compounds, i is the number of ions released per compound.
i) nonionic: 0.20 m
ii) $3\times 0.10\ m=0.30\ m$
iii) $2\times 0.12\ m=0.24\ m$
iv) $3\times 0.12\ m=0.36\ m$
a) iv, b) iv
c) i, the highest vapor pressure will be the one with the lowest vapor pressure depression.
