Which of the following processes does not involve oxidation of iron? (NEET 2015)

Potassium dichromate 2 2 7 K Cr O reacts with sulphur dioxide in presence of sulphuric acid to produce potassium sulphate, chromium (II) sulphate .the reaction is as shown below 2 2 2 7 2 4 2 4 2 4 3 2 SO + K Cr O + 3H SO K SO + Cr (SO ) + 3H O -> Chromium (II) sulphate is a green-coloured compound. Thus, (d) is the correct option. 36. When copper is heated with conc. HNO3 it produces (NEET 2016) (a) Cu(NO3)2 and NO2. (b) Cu(NO3)2 and NO. (c) Cu(NO3)2, NO and NO2. (d) Cu(NO3)2 and N2O Copper,Cu reacts with concentrated nitric acid to produce copper nitrate and nitrogen dioxide. A reactio