The major species present upon dissolution will be water and N₂O because N₂O is soluble in water.
Step-by-step explanation:
By "major species," it means, "what type are most of the atoms gift in."
N2O is an ionic compound consisting of N2+ and O- ions. it's gift as molecules within the gas section, however once value-added to water, the ions dissociate (this is true of all robust acids). that the major species gift in answer are H+ (which is typically aforementioned to react with water to make H3O+ or different complexes with water, thus place this if you want).