Which of the following reactions best represents lab scale preparation of nitric acid?

NaNO₃ + H₂SO₄ → NaHSO₄ + HNO₃

The most appropriate lab scale preparation method of nitric acid, HNO₃ is using an alkali nitrate salt and react it with concentration nitric acid in a glass retort. Nitrous acid being highly unstable decomposes into nitric acid. The other two sets of reaction represent the industrial process of manufacturing nitric acid i.e. Ostwald’s process.