Question

Balance MnO₂ + HCl → MnCl₂ + Cl₂ + H₂O

Answer 1

Solution x

Step-1: Assign oxidation number:

Step-2: Write the oxidation number changes. 

Change in oxidation number of Mn + 4 to +2 = 2 

Change in oxidation number of Cl - 1 to 0 = +1

Step-3: Cross multiply the numbers. Co-efficient 2 is multiplied to HCl and 1 is multiplied to MnO₂.

MnO₂ + 2HCl → MnCl₂ + H₂O + Cl₂

Step-4: Check the oxidation number, and 2 molecules of HCl on left hand side to balance the chlorine atoms of MnCl₂. In order to balance oxygen and hydrogen atom 2 molecule of H₂O has to be added on the right hand side.

MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂