Which of the following would produce the most ions when dissolved in water?
sodium chloride
mangesium chloride
aluminum oxide
sugar

Aluminum oxide

Explanation:

The solubility of each of the species is shown below;

Sodium chloride: NaCl(s) > Na^+(aq) + Cl^-(aq)

Magnesium chloride: MgCl2(s)> Mg^2+(aq) + 2Cl^-(aq)

Aluminum Oxide: Al2O3(s) > 2Al^3+(aq) + 3O^2-(aq)

Sugar: Not ionic in nature hence it doesn't produce any ions.

We can see that Al2O3 produces five ions in solution. This is the specie that produces the greatest number of ions among all the species listed among the options. Hence we can safely conclude that aluminum oxide is the specie that produces the greatest number of ions in solution among all the options listed in the question.