[research]

hi
imagine you have a reaction with unknown mechanism how you suggest a mechanism for it?
I mean which instruments or book or any thing else you will use to solve the problem 
every answer will be appreciated 

[dunno260]

There are rules you pick up the more you learn in organic chemistry.  The goal isn't always to suggest what the mechanism actually is, because you can't know that, but what a reasonable mechanism for the reaction is (this is important because mechanisms aren't nailed down for many organic reactions).

There are books designed to help you with this.  The one you most typically see used is Grossman's book The Art of Writing Reasonable Organic Reaction Mechanisms, but it might be a bit advanced for the introductory Organic Level.

Arrow Pushing in Organic Chemistry by Dan Levy was used in my undergrad class and it wasn't too bad.

But by learning more reactions, you see how reactions take place depending upon what that reaction conditions are.  That also controls what types of things can occur.  For instance, you aren't going to make any positively charged species in a basic environment.    Pi bonds and lots of heat tend to suggest pericyclic reactions.  Palladium catalyzed couplings broadly share mechanistic features.