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

Explanation

(i) `underset("Ethene") (C_(2)H_(4))+ underset("Oxygen")(3O_(2)) to underset("Carbon dioxide")(2CO_(2)) + underset("Water") (2H_(2)O)`
(ii) `underset("Aluminium")(4Al) + underset("Oxygen")(3O_(2)) to underset("Alumina")(2Al_(2) O_(3))`