Final answer:
H₃O⁺ and H⁺ can indeed be used interchangeably, as H⁺ in water is assumed to be in the form of hydronium ions.
Step-by-step explanation:
The statement that H₃O⁺ and H⁺ are used interchangeably is true. In aqueous solutions, H⁺ ions associate with water molecules to form hydronium ions (H₃O⁺). However, it's common in many chemical equations to simply use H⁺ for simplicity, even though the actual form in water is the hydronium ion. This interchangeability is mainly seen in acid-base reactions where the presence of water is assumed.