The substance that is not a salt among the options given is Aluminium oxide.
A salt is a type of chemical compound that is formed when an acid reacts with a base. It is typically made up of a metal cation and a non-metal anion.
Sodium hydrogentrioxosulphate (V), sodium trioxocarbonate (V), and zinc chloride are all examples of salts.
Aluminium oxide, on the other hand, is not formed from the reaction of an acid and a base. It is an oxide of the metal aluminium and is therefore not a salt.
In summary, of the substances listed, Aluminium oxide is not a salt, while sodium hydrogentrioxosulphate (V), sodium trioxocarbonate (V), and zinc chloride are all examples of salts.