Question

he established the theory of electrolytic dissociation, supplying a reasonable explanation of many chemical phenomena otherwise _____.
insoluble
barbarian
nimble
terrestrial

Explanation:

The theory of electrolytic dissociation provided explanations for chemical phenomena that were previously hard - to - explain. "Insoluble" relates to the solubility of substances in a chemical context, which makes sense here as it could refer to chemical phenomena that couldn't be explained before in terms of solubility and dissociation. "Barbarian" is a term related to culture or people, not chemistry. "Nimble" means quick and light - footed, not relevant to chemical phenomena. "Terrestrial" relates to the earth, not to chemical explanations.

Answer:

Insoluble