Complete the following reactions:
(i) `C_(2) H_(4) + O_(2) to`
(ii) `4Al + 3 O_(2) to`

Explanation

(i) `C_(2)H_(4)` undergoes combustion to form `CO_(2) and H_(2)O, C_(2)H_(4)(g) + 3O_(2)(g)overset("Heat")rarr 2 CO_(2)(g) + 2H_(2)O(g)`
(ii) Al combines with `O_(2)` to form alumina, `4 Al(s) + 3O_(2)(g) overset("Heat")rarr 2 Al_(2)O_(3)(s)`