Question

Balance the reaction in acid and base medium using half reaction method. (10 points each)

1. Cu + HNO3 → Cu⁺² + NO

Answer 1

Cu + HNO₃ → Cu⁺² + NO

Cu + HNO₃ $\to$ Cu(NO₃)₂ + NO + H₂O

We separate semi-reactions:

Cu⁰ - 2e $\to$ Cu²⁺

N⁺⁵ + 3e $\to$ N²⁺

Let's balance

charge of each equation with electrons:

3Cu⁰ - 6e $\to$ 3Cu²⁺

2N⁺⁵ + 6e $\to$ 2N²⁺

complete equation

3Cu + 8HNO₃ $\to$ 3Cu(NO₃)₂ + 2NO + 4H₂O