When the equation HCl + MnO2 → MnCl2 + H2O + Cl2 is balanced, what is the coefficient for HCl?
A. 1
B. 2
C. 3
D. 4***
4HCl + MnO2 → MnCl2 + 2H2O + Cl2
Thank you bobpursley :)
To balance the given equation: HCl + MnO2 → MnCl2 + H2O + Cl2, you need to ensure that there are equal numbers of atoms on both sides of the equation.
First, count the number of atoms for each element on both sides:
H: 1 on the left, 2 on the right
Cl: 1 on the left, 2 on the right
Mn: 1 on the left, 1 on the right
O: 2 on the right
To balance the hydrogens, you need to put a coefficient in front of HCl. Let's represent the coefficient as x. Multiplying HCl by x gives x HCl. Now you have:
x HCl + MnO2 → MnCl2 + H2O + Cl2
Now, with x HCl, the number of hydrogens is x. The number of chlorines is still 1 on the left and 2 on the right. So, to balance the chlorines, you also need a coefficient in front of Cl2. Let's represent the coefficient as y. Multiplying Cl2 by y gives y Cl2. Now the equation becomes:
x HCl + MnO2 → MnCl2 + H2O + y Cl2
Now, counting the atoms again:
H: x on the left, 2 on the right
Cl: 2y on the left, 2y on the right
Mn: 1 on the left, 1 on the right
O: 2 on the right
To balance the hydrogens, we need x = 2. So the equation becomes:
2 HCl + MnO2 → MnCl2 + H2O + y Cl2
Now counting the atoms again:
H: 4 on the left, 2 on the right
Cl: 2y on the left, 2y on the right
To balance the chlorines, we need 2y = 2, which means y = 1.
Therefore, the balanced equation is:
2 HCl + MnO2 → MnCl2 + H2O + Cl2
The coefficient for HCl in the balanced equation is 2. So the answer is option B.