Question

Balance the redox equation (acidic medium)
MnO2 + HCl –> Mn2+ + Cl2 + H2O

Answer 1

$MnO_2\rightarrow Mn^{2+}$

$MnO_2\rightarrow Mn^{2+}+2H_2O$

$MnO_2+ 4H^+\rightarrow Mn^{2+} + 2H_2O$

$MnO_2+4H^++2e^-\rightarrow Mn^{2+}+2H_2O$

$2Cl^-\rightarrow Cl_2+2e^-$

Add the last two equations:

$MnO_2+4H^++2e^-+2Cl^-\rightarrow Mn^{2+}+ 2H_2O+Cl_2+2e^-$

$MnO_2+2H^++2HCl\rightarrow Mn^{2+}+2H_2O+Cl_2$

Add $2Cl^-$ to the both sides of equation

$MnO_2+4HCl\rightarrow MnCl_2+2H_2O+Cl_2$