What is the main consequence of increasing the oxidation state in a substrate?

Increasing the oxidation state in a substrate typically involves the removal of electrons from the molecule, often resulting in the formation of more polar bonds or the generation of reactive intermediates. This change in oxidation state can make the substrate more electrophilic, meaning it has a greater tendency to react with nucleophiles. Higher oxidation states are generally associated with more potent reactive species, which can lead to increased reactivity in various chemical reactions.

Reactions such as combustion or oxidation-reduction (redox) processes illustrate how substrates at higher oxidation states can be more reactive, allowing them to participate readily in a variety of chemical transformations. In contrast, substrates at lower oxidation states might be more stable and less inclined to engage in reactions.

As for the other possibilities, it's clear that higher oxidation states do not inherently lead to the formation of only stable products; reactive intermediates are common outcomes. Expanding in size is not a direct consequence of increased oxidation; rather, changes in molecular structure can affect sterics and reactivity in complex ways, but this does not necessarily correlate with oxidation state alone. Therefore, the main consequence of increasing the oxidation state is that the substrate becomes more reactive.