Balance the equation MnO2 + HCl → Cl2 + MnCl2 + H2O using the smallest possible integer coefficients. What is the sum of the coefficient?

The sum of the coefficients is 9

MnO2 + 4HCl → Cl2 + MnCl2 + 2H2O

Explanation:

Step 1: The unbalanced equation

MnO2 + HCl → Cl2 + MnCl2 + H2O

Step 2: Balancing the equation

MnO2 + HCl → Cl2 + MnCl2 + H2O

On the left side we have 1x Cl (in HCl), on the right side we have 4x Cl (2x in Cl2 and 2x in MnCl2). To balance the amount of Cl on both sides, we have to multiply HCl, on the left side, by 4.

MnO2 + 4HCl → Cl2 + MnCl2 + H2O

On the left side we have 4x H (in 4HCl), on the right side we have 2x H (in H2O). To balance the amount of H on both sides, we have to multiply H2O, on the right side) by 2. Now the equation is balanced

MnO2 + 4HCl → Cl2 + MnCl2 + 2H2O

The sum of the coefficients is 1 + 4 + 1 + 1 + 2 = 9

MnO2 + 4 HCl = Cl2 + MnCl2 + 2 H2O

so ANS 3 is correct as there the sum is 9.