Which topics should I read in redox reaction and hydrogen?

In NEET UG, we can't predict the sub topics on particular topic - they can ask anything and everything from the important topics, that should be just a guideline
to make things simplified you give special stress to the important topics of alkali metals, alkaline earth metals, heavy metals and halogens since they are the most frequently asked Series on which you get questions related to metallurgical chemistry and ionic reactions apart from the hydrogen bonds and different organic chemistry reactions involving hydrogen apart from hydrogen being used with Palladium as a catalyst and different metrological reactions which are some of the heavily question questions from the chapter you have mentioned

I suggest you need to cover the concept of balancing of oxidation and redox reactions. In hydrogen dont forget the structures in the chapter and basic reactions. I suggest to get important topic in any chapter you need to see previous year question and know which topic they are talking about.