>>11707644Underrated, but should have been Flevorium instead of Oganesson for maximum kek
>>11708059idk about physics but usually lectures on phys chem are part of a chem degree
>>11708160That question is mainly about memorizing the reactions. "Understanding the reactions" (i.e. learning the mechanisms) helps with that, but in the end you still need to memorize the reactions.
The problem is that just identifying potential nucleophiles/electrophiles often isn't enough to easily predict what will happen, there are many other factors like steric bulk and orbital symmetry that influence reactivity.
Predicting reaction products just based on reagents is often extremely hard if you haven't memorized the reaction (or a similar reaction, so memorizing many reactions helps).
Anyways,
>but how can I tell which is the electrophile?The beginner's way: Look for positively charged atoms/molecules and atoms in high oxidation states or with lower-than-normal valence (8 electron rule for main group elements other than hydrogen, 18 electron rule for transition metals).
More advanced: Construct MO diagrams and look for low energy empty MOs.
>top leftThe electrophile (in the first step of the reaction) is Hg because it's electron deficient (14 electrons, 10 electrons from Hg(II) and 2x2 from OAc ligands).
The easy (but not quite correct) way to picture the ensuing reaction (which is called oxymercuration) is to imagine Hg(II) as a "fat proton" adding to the alkene. Two carbenium ions can result from this, one significantly more stable than the other. The more stable carbenium ion will be formed and is obviously strongly elecrophilic (positive charge, only 6 valence electrons). It will add to the nucleophile present: water.
Borohydride basically just replaces Hg with H, yielding an alcohol (i.e. not the epoxide pictured).
This reaction is analoguous to acid catalysed addition of water to alkenes, but rearrangements of the intermediatary carbenium ion don't happen with Hg(II).
