the equation for water is h₂ + o₂ → h₂o. to balance the equation, which coefficient should be placed in…

Explanation:

Step1: Analyze oxygen atoms

The un - balanced equation is $H_2+O_2\rightarrow H_2O$. On the left - hand side, there are 2 oxygen atoms in $O_2$, and on the right - hand side, there is 1 oxygen atom in $H_2O$. To balance the oxygen atoms, we need 2 moles of $H_2O$. So the equation becomes $H_2+O_2\rightarrow 2H_2O$.

Step2: Analyze hydrogen atoms

Now, in $2H_2O$, there are 4 hydrogen atoms. On the left - hand side, in $H_2$, we need 2 moles of $H_2$ to have 4 hydrogen atoms. The balanced equation is $2H_2+O_2 = 2H_2O$.

Answer:

2