Assertion :N2 is adsorbed on iron surface at 83 K which decreases rapidly with increase in temperature and at room temperature, practically no adsorption of N2 occurs. The adsorption, however, becomes significant at 773 K. Reason: At lower temperature, adsorption of N2 molecules on iron surface is physisorption and at high temperatures, N2 shows chemisorption of N atoms on iron surface.