Sodium stearate solution and sodium dodecylbenzenesulphonate solution are each acidified with dilute HCl. Only the first turns turbid. The best explanation is that

1. AHCl reacts with the benzene ring of the detergent to make it more soluble
2. Bstearic acid is a weak acid, so the stearate ion is protonated to insoluble $\mathrm{C}{}_{17}\mathrm{H}{}_{35}\mathrm{COOH}$, whereas the sulphonic acid is a strong acid and its anion stays ionised
3. Cthe sulphonate ion is a stronger base than stearate and consumes all the $\mathrm{H}{}^{+}$
4. Dstearate ions are oxidised by HCl, but sulphonate ions are not