Question

1. choose the best answer.

the following shows chemical equations that students have recorded in their lab journals after performing several experiments.
experiment equation
experiment 1 4fe(s) + 3o₂(g) → 2fe₂o₃(s)
experiment 2 cu(s) + agno₃(aq) → cuno₃(aq) + ag(s)
experiment 3 pb(no₃)₂(aq) + 2ki(aq) → pbi₂(s) + 2kno₃(aq)
which of these is a solid?
pb(no₃)₂
pbi₂
agno₃
kno₃

Explanation:

To determine which substance is a solid, we analyze the state symbols in the chemical equations:

• \( \text{Pb(NO}_3\text{)}_2 \) has the state symbol \( (aq) \), meaning it is aqueous (dissolved in water), not a solid.
• \( \text{PbI}_2 \) has the state symbol \( (s) \), which stands for solid.
• \( \text{AgNO}_3 \) has the state symbol \( (aq) \), so it is aqueous, not a solid.
• \( \text{KNO}_3 \) has the state symbol \( (aq) \), so it is aqueous, not a solid.

Answer:

\( \text{PbI}_2 \) (the option with \( \text{PbI}_2 \))