Sn1: the nerdy scientist gent
The Sn1 nucleophile is shy. He is "weak." He is a nice guy. He is meek (in a Christ-like way). He is a gentleman. He waits for the carbon lady to finish talking to her pal Clara or Bromina. The carbon electrophile has to make the first move at which point he is drawn to her. Carbon electrophile might pull an oldie but a goodie tactic and say, "All the guys on the planet are gone and I really want to see this new movie, but I don't know any guys around who can take me."
So nerdy nucleophile comes to her aid. Now, because carbon electrophile is alone with no leaving group to comfort her, nerdy nucleophile can ask her out from the front or the back. She is open to his charms. Substitution is complete front or back and you get a racemic mixture.
Protic solvent? Cock blockers? Protic solvents only work to help the carbon electrophile lady to feel more comfortable without her gal pal there. Cock blockers are doing the same. It's all about how relaxed and stable the carbon electrophile is while her gal pal is in the bathroom.
And that my friends is the difference between Sn2 and Sn1. I like this analogy because most of female clients have been in a situation where the guy asking her out in a bar was a jerk. Most male clients can relate to this story as well. I'm tutoring college students normally so what does it hurt to bring up drinking in bars?
Right? Comment below.
For Sn2 "the jerk" please see my previous blog entry.