Most powerful oxygen free radical is:: (A) Hydroxyradical, (B) Hydrogen peroxide, (C) Superoxide radical, (D) Both 1 & 2
Answer is A. Most powerful oxygen free radical is Hydroxyradical:

Least powerful Reactive Oxygen species 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 by Rebecca James Perumcheril Pg-411