Cu+HNO3=?

The reaction between copper (Cu) and nitric acid (HNO₃) can vary depending on the concentration of the nitric acid used.

1. With dilute nitric acid: When copper reacts with dilute nitric acid, it typically produces copper(II) nitrate (Cu(NO₃)₂), nitrogen monoxide (NO), water (H₂O), and some hydrogen ions (H⁺). The balanced equation for this reaction is:

   \[ Cu + 4 HNO_3 (dilute) \rightarrow Cu(NO_3)_2 + 2 NO + 2 H_2O \]

2. With concentrated nitric acid: When copper reacts with concentrated nitric acid, the products include copper(II) nitrate, nitrogen dioxide (NO₂), and water. The balanced equation for this reaction is:

   \[ Cu + 4 HNO_3 (conc.) \rightarrow Cu(NO_3)_2 + 2 NO_2 + 2 H_2O \]

In summary, depending on the concentration of HNO₃, different nitrogen oxides can be produced along with copper(II) nitrate and water.