Final answer:
The given compounds are classified based on their ability to produce hydrogen ions or hydroxide ions in solution. HCN, HClO4, and H2C2O4 are acids; Sr(OH)2 and RbOH are bases; (NH4)2SO4, KI, and CaCl2 are salts.
Step-by-step explanation:
To classify the given compounds as acids, bases, or salts, we need to look at their composition and the ions they form in aqueous solutions. Compounds that release hydrogen ions (H+) in solution are acids, compounds that release hydroxide ions (OH-) or accept H+ are bases, and salts are typically formed from the neutralization reaction between an acid and a base.
- HCN is a weak acid as it can release H+ ions in solution.
- (NH4)2SO4 is a salt, formed from the reaction of the weak base ammonium hydroxide (NH4OH) and the strong acid sulfuric acid (H2SO4).
- HClO4 is a strong acid.
- H2C2O4 is oxalic acid, which is a weak acid.
- Sr(OH)2 and RbOH are strong bases as they contain the hydroxide ion (OH-).
- KI and CaCl2 are salts. KI is formed from potassium hydroxide (a strong base) and hydroiodic acid (a strong acid), while CaCl2 is formed from calcium hydroxide (a strong base) and hydrochloric acid (a strong acid).