Question

hO2 là j

Answer 1

This is the chemical formula for the hydroperoxyl radical.It is a very important molecule in atmospheric and combustion chemistry.

Answer 2

The hydroperoxyl radical is an extremely reactive chemical species.

Formula:HO2​ orHOO⋅ Classification: It is the simplest peroxy radical and is part of theHOx​ family, which includes the hydroxyl radical (OH⋅). It is also a form of Reactive Oxygen Species (ROS). Structure: The molecule has a bent structure (non-linear) consisting of a hydrogen atom bonded to two oxygen atoms, with an unpaired electron on one of the oxygen atoms (making it a radical). Conjugate Acid/Base Pair:HO2​⋅ is the protonated form of the superoxide anion (O2−​⋅). They exist in rapid equilibrium in an aqueous solution: O2−​⋅+H2​O⇌HO2​⋅+OH−ThepKa​ ofHO2​⋅ is about4.88. This means that at the physiological pH of a cell (∼7.4), most of the species is in the form of the superoxide anion (O2−​⋅).

2. Importance in Atmospheric Chemistry

In the atmosphere (specifically the troposphere), HO2​⋅ plays a central role in complex photochemical cycles that govern air quality. It acts as an oxidizing agent and a chain-carrier for reactions.

	Key Reactions
Ozone (O3​) Formation	In polluted environments (high NOx​ ), HO2​⋅ converts nitric oxide ( NO ) into nitrogen dioxide ( NO2​ ), which then photolyzes to produce ground-level ozone, a major component of smog.	HO2​⋅+NO→OH⋅+NO2​
Recycling the Hydroxyl Radical	This reaction with NO regenerates the highly reactive hydroxyl radical ( OH⋅ ), sustaining the atmospheric oxidation chain.	HO2​⋅+NO→OH⋅+NO2​
Hydrogen Peroxide (H2​O2​) Source	The self-reaction (or termination reaction) of two HO2​⋅ radicals is the main source of hydrogen peroxide ( H2​O2​ ) in the gas phase. H2​O2​ is then important for liquid-phase chemistry in clouds.	HO2​⋅+HO2​⋅→H2​O2​+O2​
Oxidation of Organics	HO2​⋅ (and its organic version, RO2​⋅ ) react with and degrade organic pollutants (Volatile Organic Compounds or $\text{VOC}$s), acting as an atmospheric "cleanser."	RO2​⋅+HO2​⋅→ROOH+O2​

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3. Importance in Cell Biology

In living systems, theHO2​⋅/O2−​⋅ pair is an essential Reactive Oxygen Species (ROS) involved in cellular signaling, defense, and damage.

Oxidizing Agent: Unlike its conjugate base, the superoxide anion (O2−​⋅), the unchargedHO2​⋅ is a strong oxidant. Initiator of Lipid Peroxidation:HO2​⋅ can abstract hydrogen atoms from unsaturated fatty acids in cell membranes, initiating a chain reaction called lipid peroxidation, which can lead to cell damage and is implicated in aging and disease. Cell Penetration: Since HO2​⋅ is a neutral molecule, it can more easily cross lipid bilayers and cell membranes than the charged superoxide anion (O2−​⋅), potentially transferring radical damage between cellular compartments.

Answer 3

"ho2" thường dùng để chỉ gốc tự do hydroperoxyl (hoặc hydro superoxide), có công thức hóa học là HO₂. Đây là một dạng ion của superoxide được proton hóa, có vai trò quan trọng trong các quá trình hóa học ở khí quyển và sinh học tế bào.