largest dipole moment, some other stuff?

Question

does CO2, H2O, CH4, C2H4, or PH3 have the largest dipole moment? i would guess c2h4, but i am not sure.

and, out of:
PbSO4, CuO, KMnO4, KCl, FeCl3
Which:
>is purple in aqueous solution?
>is white and very soluble in water?

Answer 1

H2O, because the charge difference is greatest between H, electronegativity 2.2 and O, 3.5.

KMnO4 is purple. KCl is water-white and very water soluble.

Answer 2

There was an article in Scientific American about a year ago which describe some study of this, but it was not to determine an internal structure so much as looking for ways to use this factor in Development of new digital storage methods.