Which of the following is most polar?

Among the following mixtures,in which is dipole-dipole attraction present?

The geometry and dipole moment of $H_2S$ respectively are

The most polar bond is

Give the correct order of initials $T$ or $F$ for the following statements. Use $T$ if the statement is true and $F$ if it is false.
$I. \, (CH_3)_2P(CF_3)_3$ is non-polar and $(CH_3)_3P(CF_3)_2$ is a polar molecule.
$II. \, CH_3 \widehat{P} CH_3$ bond angles are equal in the $(CH_3)_3P(CF_3)_2$ molecule.
$III. \, PF_3$ will be more soluble in a polar solvent than $SiF_4$.

Write the significance and applications of dipole moment.