This is an oxidation reduction reaction oxidation happens when the species gives out electrons.Oxidation state of the element Cu increases from 0 to +2 Cu ---> Cu²⁺ +2e --1) Reduction happens when the species gains electrons. Oxidation state of N reduces from +5 to +2 4H⁺ + NO₃⁻ + 3e ---> NO + 2H₂O --2) To balance the reactions, number of electrons need to be balanced. Multiply 1st reaction by 3 Multiply 2nd reaction by 2 3Cu ---> 3Cu²⁺ + 6e 8H⁺ + 2NO₃⁻ + 6e ---> 2NO + 4H₂O add the 2 equations 3Cu + 8H⁺ + 2NO₃⁻ --> 3Cu²⁺ + 2NO + 4H₂O add 6NO₃⁻ ions to each side 3Cu + 8HNO₃ --> 3Cu(NO₃)₂ + 2NO + 4H₂O the balanced redox reaction equation is as follows;
