So if a reaction takes place on an unsymmetrical compound such as this alkane, unsymmetrical simply means if we cut this in half, the left is different from the right. So if a reaction takes place on an oxymetrical compound, different pathways are possible. And this is known as regiochemistry. Regeochemistry is basically the study of the different pathways that our two reactants can take. Now, in the reaction above, pathway one is more favorable, it's more likely to occur. And that's because this intermediate carbocation, this tertiary carbocation is more stable than this primary carbocation.