Which of the following is not a free radical, but it is a reactive oxygen species?: (A) Hydroxyradical, (B) Hydrogen peroxide, (C) Superoxide radical, (D) Both 1 & 2
Answer is B. Most powerful oxygen free radical is Hydroxyradical.
Least powerful Reactive Oxygen species(ROS) is Hydrogen peroxide.
Precursor of all Reactive Oxygen species is Superoxide radical.
H2O2 is not a free radical,  but a ROS.

Reference- Review of biochemistry Pg-411