Why are SN2 reactions better in aprotic? (Poor solvation of the nucleophile favors SN2, while poor solvation of the leaving group disfavors SN1. - GS). Are both Sn2 and Sn1 reactions better in polar vs nonpolar? (Yes. Polarity helps formation of a carbocation (for SN1) and helps to dissolve the nucleophile (for both SN2 and SN1). - GS).

Can we please re-discuss why protic solvents cause products to form faster and why they are more favored than aprotic solvents in SN1 reactions? (Because protic solvents solvate anions in addition to carbocations. - GS).

Can you explain conformation vs configuration?  (Configuration can be changed only by breaking chemical bonds. Conformation changes when a molecule adopts a different shape, without breaking bonds. - GS). So E/Z would be considered a configuration? (Yes. - GS). Okay, thanks!

What is the difference between NaNh2 and Na, NH3 (This first reagent is a strong base, the second one is a strong reducing agent. - GS).

Why does halogenation of alkynes make stereoselectivity of addition unpredictable? (Because the 3-membered bromonium responsible for anti-stereoselectivity, is unstable (too strained) - GS).

What are other ways to create an acetylenide other than using NaNH2? (Grignard reagents, alkyllithium compounds, such as Butyl lithium - GS).

Will you please explain the difference between cationic polymerization of alkenes and free radical polymerization of alkenes. And how that compares to addition of HCl to alkenes. (Both cationic polymerization and electrophilic addition of HCl start from protonation  of C=C. Radical polymerization starts from the attack of C=C by a free radical. - GS).