I know the basics but I have not done jee advance level question on it. Should I leave it here or solve jee advance level questions?

# Is 2nd order Reaction in Chemical kinetics is too important for jee?

Only basic questions of 2nd order and higher order reaction are asked in exams .. for example the conc vs time graph or T1/2 vs time graph .

So no need to invest much of your time into it .. just remember the proportionality of T1/2 with Time , etc

It isn't specified specifically in the syllabus but if you're interested read the theory and formula in RC Mukherjee

It's enough for JEE

It isn't in detail

Just go for solving the pre year problems...and if you encounter problems related to 2nd order reactions,then you may try solving more sums similar to those from different sources or the ones which uses the concepts and formulas similar to the ones in those pre yea questions.

In my opinion too, knowing the basics is just fine. For that matter you can derive the formula for any n-order reaction. Just remember the concept and you can easily solve questions related to 2nd or higher degree reactions