Final answer:
Cations are positively charged ions, and among the given options, H⁺ (hydrogen ion) and Ag⁺ (silver ion) are cations because they carry a positive charge.
Step-by-step explanation:
Cations are positively charged ions. The given options contain a mix of cations and anions. To identify which of the following are cations, we look for a positive charge associated with the particle:
- H⁺ - This is a hydrogen ion with a positive charge, therefore it is a cation.
- OH⁻ - This is a hydroxide ion with a negative charge, therefore it is not a cation.
- Ag⁺ - This is a silver ion with a positive charge, hence it is a cation.
- CO₂⁻ - This represents a carbonate ion with a negative charge, so it is not a cation.
Therefore, the correct answers are H⁺ and Ag⁺, which are both cations.