Final answer:
Compound a, Ba(OH)2, is a strong base in aqueous solution. Compound b, HIO4, is a strong acid in aqueous solution.
Step-by-step explanation:
Compound a. Ba(OH)2 is a strong base in aqueous solution. Ba(OH)2 dissociates completely into Ba2+ and OH- ions in water, making it a strong base.
Compound b. HIO4 is a strong acid in aqueous solution. HIO4 dissociates completely into H+ and IO4- ions in water, making it a strong acid.