Question

Al + HNO3 arrow Al (NO3)3 +NH4NO3+H2O​

Answer 1

 This is an oxidation-reduction (redox) reaction:

8 Al0 - 24 e- → 8 AlIII (oxidation)

3 NV + 24 e- → 3 N-III (reduction)

Al is a reducing agent, HNO3 is an oxidizing agent.