A double replacement chemical equation is shown:

_MnO2 + _HCI → _MnCI2 + _H2O + _CI1
What values should be inserted into the blanks as coefficients to ensure the preservation of the law of conservation of matter?

1 answer

To balance the chemical equation \( \text{MnO}_2 + \text{HCl} \rightarrow \text{MnCl}_2 + \text{H}_2\text{O} + \text{Cl}_2 \), we need to ensure that the number of each type of atom is the same on both sides of the equation.

Let's break it down step-by-step:

  1. Count the atoms of each element on both sides:

    • Reactants:

      • Mn: 1 (from \( \text{MnO}_2 \))
      • O: 2 (from \( \text{MnO}_2 \))
      • H: 1 (from \( \text{HCl} \))
      • Cl: 1 (from \( \text{HCl} \))
    • Products:

      • Mn: 1 (from \( \text{MnCl}_2 \))
      • Cl: 2 (from \( \text{MnCl}_2 \)) + 2 (from \( \text{Cl}_2 \)) = 4 total Cl
      • H: 2 (from \( \text{H}_2\text{O} \))
      • O: 1 (from \( \text{H}_2\text{O} \))
  2. Start balancing:

    • The manganese (Mn) atoms are balanced (1 on each side).
    • We need to balance the chlorine (Cl) and hydrogen (H) atoms. To do this:
      • Place a coefficient of 4 in front of \( \text{HCl} \) on the left side to yield 4 Cl and 4 H, and we also keep the \( \text{MnO}_2 \) for oxygen balance.
      • We now have: \[ \text{MnO}_2 + 4\text{HCl} \rightarrow \text{MnCl}_2 + 2\text{H}_2\text{O} + \text{Cl}_2 \]
    • Now go through each element again to confirm balance:
      • Mn: 1 on both sides
      • O: 2 (from \( \text{MnO}_2 \)) and 2 (from 2 \( \text{H}_2O \))
      • H: 4 on the left (from \( 4 \text{HCl} \)) and 4 on the right (from \( 2 \text{H}_2O \))
      • Cl: 4 from \( 4 \text{HCl} \) and 2 (from \( \text{MnCl}_2 \)) + 2 (from \( \text{Cl}_2 \)) = 4 on the right side
  3. Final balanced equation: \[ 1\text{MnO}_2 + 4\text{HCl} \rightarrow 1\text{MnCl}_2 + 2\text{H}_2\text{O} + 1\text{Cl}_2 \]

  4. Insert the coefficients: Therefore, the final coefficients for the equation are:

    • MnO2: 1
    • HCl: 4
    • MnCl2: 1
    • H2O: 2
    • Cl2: 1

So, the coefficients inserted would be:

1, 4, 1, 2, 1.