In what ways can nitric acid be obtained? Write the reaction equations

HNO3-nitric acid
You can get it
H2O + 3NO2 = 2HNO3 + NO
4KNO3 + 2FeSO4 ∙ 7H2O → Fe2O3 + 2K2SO4 + 2HNO3 ↑ + 2NO2 ↑ + 6H2O
KNO3 + H2SO4 → KHSO4 + HNO3
1) conversion of ammonia in order to obtain nitrogen oxide
4NH3 + 5O2 → 4NO + 6H2O;
2) oxidation of nitric oxide to nitrogen dioxide
2NO + O2 → 2NO2;
3) absorption of nitrogen oxides by water
4NO2 + O2 + 2H2O → 4HNO3;