How do you balance Mn+HI→H2+MnI3?

1 Answer
Ernest Z.
Mar 5, 2016

You can balance it by inspection.

Explanation:

The procedure I usually use is:

  1. Start with the most complicated formula.
  2. Balance all atoms other than H and O.
  3. Balance O.
  4. Balance H.
  5. If necessary, multiply by an integer to remove fractions.
  6. Check that all atoms are balanced.

Your unbalanced equation is

Mnl+HI→H2+MnI3

Step 1. Start with the most complicated formula.

Put a 1 in front of MnI3. This number is fixed and does not change until (if necessary) Step 5.

Mnl+HI→H2+1MnI3

Step 2. Balance Mn.

We have fixed 1 Mn on the right, so we need 1 Mn on the left.

1Mn+HI→H2+1MnI3

Step 3. Balance I.

We have fixed 3 I on the right, so we need 3 I on the left.

Put a 3 before HI.

1Mn+3HI→H2+1MnI3

Step 4. Balance H.

We have fixed 3 H on the left, so we need 3 H on the right.

We have 2 H atoms on the right, so we must multiply by 1.5 to get 3 H atoms.

1Mn+3HI→1.5H2+1MnI3

All atoms should now between balanced, but we have a fraction in front of H2

Step 5. Multiply all coefficients by 2 to remove fractions.

2Mn+6HI→3H2+MnI3

Step 6. Check that all atoms are balanced.

On the leftlOn the right
mll2 Mnmmmm2 Mn
mll6 Hmmmmm6 H
mll6 Immmmml6 I

The balanced equation is

2Mn+6HI→3H2+MnI3

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