Which of the following compounds will have the largest value for the vanthu factor? All right, so for the first one, we have aluminum chloride, which is an ionic compound, so it breaks up into ions. It's composed of 1 aluminum ion and three chloride ions. So in total that's four ions. So I=4.

For the next one, it's covalent because it's only nonmetals together, so I=1. For the next one, it's ionic again because zinc is a metal. Oxygen is a nonmetal, so it breaks up into zinc ion and oxide ion. That's two ions total, so I=2.

Next we have ammonium, which is NH₃. It's covalent because it's only nonmetals, so I=1 and then we have P₂S₅ which is also covalent. It's only nonmetals together, so I=1. We can see the one with the greatest Van Hoff factor value is I=4 for aluminum chloride. So here the answer would be option A.