can a 2x4 withstand 200lbs out pressure on the 1.5" side?
TL;DR -If the question is if you can use a 2x4 for a post, then the answer is no.



For guardrails see here, page 42 -6A (Chicago Deck Code).

Whatever a 2x4 can withstand is irrelevant. Guardrail posts are to be at minimum 4x4s. 

The top rail is to be a 2x6 with a 'cap'. 

Maximum span for a railing between two posts is 4'. 

Use at minimum 5/8ths through bolts with 2" - 3/16ths washers to secure the post to the ledger board (and unless you want to do it again in five years, buy all stainless fasteners).