Reaction step naming

[Marc Farah 3D]

Are electrophilic addition reactions always two step?
Does S2N mean the reaction goes from 2 molecules in the reactants to 2 molecules in the products?

[feodora_r_3d]

Yes, electrophilic addition is always two step. For SN2, its basically substitution. The two reactants are usually a reaction between a hydrocarbon with substituent attached to one of its carbon (for example Bromine) and another molecule (example OH). So what it means by substitution is the substituent in the hydrocarbon chain will switch places with the other molecule it is reacting with (which in this example is the OH). So the Bromine and OH exchange places. OH attaches to the carbon, and Br becomes Br- and is not attached to anything.
hope this helps!

[Sydniespore]

SN2 is a one step and Electrophillic addition is two steps.

[Cayla_Brooks_1I]

do we need to be able to write the biproduct in the Sn2 reactions. For example on problem 5 part C. the OH that breaks off is now included in the final answer.