The skeleton equation is:
`Mg_(2) C_(3) (s) + H_(2) O (l) rarr CH_(3) - C -= CH (g) + Mg (OH)_(2) (s)`
a. Order of selection of atoms for balancing `Mg, O, H`, and `C`.
b. To equalise the number of `Mg` atoms on both sides, multiply the molecule of `Mg (OH)_(2)` by 2.
`Mg_(2) C_(3) (s) + H_(2) O (l) rarr CH_(3) - c -= CH (g) + 2 Mg (OH)_(2) (s)`
c. To equalise the number of `O` atoms on both sides, multiply th molecule of `H_(2) O` by 4.
`Mg_(2) C_(3) (s) + 4 H_(2) O (l) rarr CH_(3) - C -= CH (g) + 2 Mg (OH)_(2) (s)`
It is balanced chemical equation.