Consider the surfactants P: $\mathrm{C}{}_{15}\mathrm{H}{}_{31}\mathrm{COONa}$; Q: $\mathrm{C}{}_{12}\mathrm{H}{}_{25}\mathrm{OSO}{}_3\mathrm{Na}$; R: $[\mathrm{C}{}_{16}\mathrm{H}{}_{33}\mathrm{N}(\mathrm{CH}{}_3){}_3]{}^{+}\mathrm{Br}{}^{-}$; S: $\mathrm{C}{}_{17}\mathrm{H}{}_{35}\mathrm{COO}(\mathrm{CH}{}_2\mathrm{CH}{}_2\mathrm{O}){}_n\mathrm{CH}{}_2\mathrm{CH}{}_2\mathrm{OH}$. Which statements are correct?

1. AR is a quaternary ammonium salt.
2. BQ and R are both anionic.
3. CS is non-ionic, so its cleansing action is not lost through ion exchange with hard-water ions.
4. DP gives a scum with $\mathrm{Ca}{}^{2+}$ and forms an insoluble acid on acidification.