The user wants to connect pairs of substances that will react with each other. Identify which of the given substances will react and provide the chemical reaction for each pair.

Solution:

• NaOH reacts with HNO₃ because it is an acid-base neutralization reaction.

Reaction: NaOH + HNO₃ → NaNO₃ + H₂O

• CaCO₃ reacts with HNO₃ because it is an acid reacting with a carbonate, producing salt, water, and carbon dioxide.

Reaction: CaCO₃ + 2HNO₃ → Ca(NO₃)₂ + H₂O + CO₂

• CuSO₄ reacts with NaOH because it is a reaction between a salt and a base, forming a precipitate.

Reaction: CuSO₄ + 2NaOH → Cu(OH)₂↓ + Na₂SO₄

• AgCl is a precipitate and generally does not react with the other given substances under normal conditions.
• Cu (copper) is a relatively unreactive metal and would not react with NaOH or AgCl. It would react with HNO₃, but it's a more complex reaction than the others presented and usually involves concentrated nitric acid.

Answer:

• NaOH + HNO₃
• CaCO₃ + HNO₃
• CuSO₄ + NaOH