which chemical equation is unbalanced?\no c + o₂ → co₂\no sr + o₂ → 2sro\no 6h₂ + 3o₂ → 6h₂o\no h₂ + h₂ + o₂…

Explanation:

Step1: Analyze first equation

In $C + O_2\rightarrow CO_2$, there is 1 C - atom and 2 O - atoms on both sides, so it is balanced.

Step2: Analyze second equation

In $Sr+O_2\rightarrow 2SrO$, there is 1 Sr - atom on the left and 2 Sr - atoms on the right, and 2 O - atoms on the left and 2 O - atoms on the right. It is unbalanced as the number of Sr - atoms is not equal on both sides.

Step3: Analyze third equation

In $6H_2 + 3O_2\rightarrow 6H_2O$, there are $6\times2 = 12$ H - atoms and $3\times2=6$ O - atoms on the left, and $6\times2 = 12$ H - atoms and 6 O - atoms on the right. It is balanced.

Step4: Analyze fourth equation

In $H_2 + H_2+O_2\rightarrow H_2O + H_2O$, there are $2 + 2=4$ H - atoms and 2 O - atoms on the left, and $2\times2 = 4$ H - atoms and $2\times1 = 2$ O - atoms on the right. It is balanced.

Answer:

Sr + O₂ → 2SrO