Final answer:
Chemical Shift of the 'Second Kind' is a subtle variation in NMR chemical shifts due to isotope substitution, affecting protons in aromatic and anomeric positions in organic molecules.
Step-by-step explanation:
Chemical Shift of the 'Second Kind' refers to the subtle changes in the NMR chemical shift of a nucleus (usually a proton) that occur due to the replacement of another atom in the molecule, such as during isotope substitution. This shift arises because different isotopes of an element have different nuclear magnetic moments and, therefore, cause a nucleus in a molecule to experience a slightly different local magnetic field. This shift is particularly important when dealing with aromatic proton shifts and anomeric proton shifts, as observed in the NMR spectra of various organic compounds, including nucleosides and their complexes.For example, the chemical shifts in different aromatic protons or anomeric protons could vary slightly due to the presence of different isotopes within the sample or the surrounding environment. In the context of the water-gas shift reaction, it refers to the shift in equilibrium between certain chemical species, which plays a crucial role in the production of key industrial gases like hydrogen.