Final answer:
HNO2 reacts with dissolved copper to form nitrogen dioxide (NO2).
Step-by-step explanation:
When HNO₂ is mixed with dissolved copper, it reacts to form nitrogen dioxide (NO₂). The reaction can be represented by the following equation:
HNO₂ + Cu → Cu(NO₂)₂ + NO₂
In this reaction, the copper is oxidized while the nitric acid (HNO₂) is reduced.