All are free radicals except
High-Yield Explanation
Hydrogen peroxide is a reactive oxygen species but not a free radical because all electrons are paired. Clinical correlate: Chronic granulomatous disease also knows as Bridges-Good syndrome is due to deficiency of NADPH oxidase. The lysosomes are unable to produce hydrogen peroxide to kill the bacteria. The patients have increased susceptibility towards catalase-positive organisms. Reference: Harpers illustrated biochemistry 30th edition