Which is the balanced chemical equation showing hydrogen peroxide (h2o2) decomposing into hydrogen (h2) and oxygen (o2)? 1. h2 + o2 → h2o2 2. 2 h2o2 → 2 h2 + o2 3. h2o2 → h2 + o2 4. 2 h2 + o2 → 2 h2o2?

The correct answer is 3) 

It's 3)

H2O2 → H2 + O2 

as the balanced equation should be the number of each atom is equal on both sides of the reaction equation.

and here we have 2 H atoms on both sides 

and 2 O atoms on both sides

so here we have an equal number of O and H atoms on both sides of the equation so (3) is the correct answer.

not 1):

because of it is not a decomposition reaction that means that the reaction should be H2O2 → H2+O2 not H2+O2→ H2O2 

so, this is not the true one.

not 2):

because we have here 4 O atoms on the left side and only 2 atoms on the

right side so, this is not a balanced equation, because we should have the same number of atoms on both sides.

not 4): 

because this is not a decomposition reaction as it not H2O2 → H2 + O2 

and also the number of O atoms not equal on both sides of the equation