Question

what is the correct reaction for when copper and concentrated nitric acid react? select one: cu(s) + hno₃(aq) → cuhno₃(aq) 2cu(s) + 2hno₃(aq) → h₂(g) + 2cuno₃(aq) cu(s) + 4hno₃(aq) → cu(no₃)₂(aq) + 2h₂o(l) + 2no₂(g) 2cu(s) + hno₃(aq) → h(g) + cu₂no₃(aq) cu(s) + hno₃(s) → h(g) + cuno₃(aq)

Explanation:

• For the first option: \(Cu(s)+HNO_3(aq)\to CuHNO_3(aq)\), this is not a valid chemical reaction as copper does not simply combine with nitric acid in this way.
• For the second option: \(2Cu(s)+2HNO_3(aq)\to H_2(g)+2CuNO_3(aq)\), when copper reacts with nitric acid, hydrogen gas is not produced. Nitric acid is a strong oxidizing agent.
• For the third option: \(Cu(s)+4HNO_3(aq)\to Cu(NO_3)_2(aq)+2H_2O(l)+2NO_2(g)\), this is the correct reaction. Copper reacts with concentrated nitric acid. Copper is oxidized to \(Cu^{2 +}\) (forming \(Cu(NO_3)_2\)), and \(NO_3^-\) in nitric acid is reduced to \(NO_2\).
• For the fourth option: \(2Cu(s)+HNO_3(aq)\to H(g)+Cu_2NO_3(aq)\), hydrogen gas is not produced, and the formula \(Cu_2NO_3\) is incorrect.
• For the fifth option: \(Cu(s)+HNO_3(s)\to H(g)+CuNO_3(aq)\), nitric acid is in aqueous form (\(aq\)) not solid (\(s\)) in this reaction, and hydrogen gas is not produced.

Answer:

\(\text{Cu}(s)+4\text{HNO}_3(aq)\to\text{Cu}(\text{NO}_3)_2(aq)+2\text{H}_2\text{O}(l)+2\text{NO}_2(g)\)