1. The problem statement, all variables and given/known data In my book there is a reaction given that is: MnO2+4HCl→MnCl2+Cl2+2H2O To prepare Cl2. And then it is given that in place of HCl, a mixture of H2SO4+NaCl is used.... but why? 2. Relevant equations None 3. The attempt at a solution NaCl+H2SO4→NaHSO4+HCl We here also get HCl. So why should we not use HCl directly? Why should be prefer the latter method?