The reaction between dichromate ions and iron (II) ions can be carried in the presence of either dilute HCl (or) sulphuric acids. But the dilute HCl cannot be used to acidify the solution for titration between Iron (II) and permanganate ion system. The reason for this is ________.

PLACEHOLDER ANSWER - the answer is a reason. Permanganate is a stronger oxidising agent than dichromate ($$E^\circ \approx 1.51\text{ V}$$ against $$1.33\text{ V}$$, with $$\text{Cl}_2/\text{Cl}^-$$ at $$1.36\text{ V}$$). So permanganate also oxidises chloride ions to chlorine, $$2\text{MnO}_4^- + 16\text{H}^+ + 10\text{Cl}^- \rightarrow 2\text{Mn}^{2+} + 5\text{Cl}_2 + 8\text{H}_2\text{O}$$. Extra permanganate is consumed and the titre is too high, while dichromate does not oxidise chloride, so HCl can be used with it.