To solve the given question, let's carefully consider the details of the chemical reaction:
[tex]\[ \text{KI} (aq) + \text{AgNO}_3 (aq) \rightarrow \text{AgI} (s) + \text{KNO}_3 (aq) \][/tex]
1. Reactants:
- KI (potassium iodide) in aqueous solution.
- AgNO₃ (silver nitrate) in aqueous solution.
2. Products:
- AgI (silver iodide) forms as a solid.
- KNO₃ (potassium nitrate) remains in aqueous solution.
One key observation in this reaction is the formation of AgI (silver iodide) in the solid state, denoted by (s). When a solid forms from the mixing of two aqueous solutions, that solid is termed a precipitate.
Explanation of each option:
- A. A mixture: A mixture can refer to any combination of substances. Given that one reactant is forming a solid, it is more specific to call it a precipitate rather than just a mixture.
- B. Water: Water is not formed in this reaction. Therefore, this option is incorrect.
- C. A precipitate: A precipitate is a solid that forms out of a solution. Since AgI is formed as a solid in this reaction, this is the correct description.
- D. A gas: There is no gaseous product in this reaction. So, this option is incorrect.
Therefore, the correct answer to the question is:
C. A precipitate
