Which one of the following permanga-nometric titrations does not give satisfactory results ?

KMnO₄ acts as a good oxidizing agent in presence of dil. H₂SO₄. But not with HCl because  It reacts with KMnO₄ solution and gets oxidized which further results in the liberation of chlorine gas

$$\begin{gathered} 2{\mathrm{KMnO}}_4+5{\mathrm{H}}_2{\mathrm{C}}_2{\mathrm{O}}_4+3{\mathrm{H}}_2{\mathrm{SO}}_4⟶{\mathrm{CO}}_2+{\mathrm{Mn}}^{+2} \\ 10 \mathrm{KI}+2{\mathrm{KMnO}}_4+16\mathrm{HCl} ⟶ {\mathrm{Fe}}^{+3}+{\mathrm{Mn}}^{+2} \\ 10\mathrm{KI}+2{\mathrm{KMnO}}_4+16\mathrm{HCl} ⟶{\mathrm{Cl}}_2+{\mathrm{Mn}}^{+2}(\mathrm{not} \mathrm{satisfactory}) \\ 2{\mathrm{KMnO}}_4+3{\mathrm{MnSO}}_4+2{\mathrm{H}}_2\mathrm{O}⟶{\mathrm{Mn}}^{+7}+{\mathrm{Mn}}^{+2} \end{gathered}$$