4 Write word equations for the following chemical reactions.
(a) Octane gas is burnt with oxygen in a car engine
to produce carbon dioxide and water.
(b) Sodium metal reacts with chlorine gas to form
sodium chloride.
(c) Hydrogen gas and oxygen gas combine to form
water.
(d) Zinc metal dissolves in hydrochloric acid to
form hydrogen gas and zinc chloride.

The correct answer is "atomic weight".

The activity series is shown in the attached picture. if the element is below the other, then you can displace the other. following the activity series as a guide, the reactions are as follows: nickel and aluminum chloride3 ni + 2 alcl₃  → 3 nicl₂ + 2 albarium and copper bromideba + cubr  →  no reaction because cu is less oxidizable than bapotassium nitrate and aluminum3 kno₃ + al  → al(no₃)₃ + 3 ksodium phosphate and zincnaso₄ + zn  → znso₄ + na