Why HF can't reduce H2SO2?

I read that $\ce{H\_2SO\_2}$ is an extremely unstable acid, so shouldn't even a weak reducing agent like $\ce{HF}$ be able to reduce $\ce{H\_2SO\_2}$ to $\ce{S}$ or something along similar lines?




No offence to Ivan Neretin, but I afraid, $\ce{H2SO2}$ (Sulfoxylic Acid) exists ([Ref. 1](https://pubs.acs.org/doi/10.1021/jp400742q)), which states that:



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> Sulfoxylic acid ($\ce{HOSOH}$), a chemical intermediate roughly midway along the path between highly reduced ($\ce{H2S}$) and highly oxidized sulfur ($\ce{H2SO4}$), has been detected using Fourier transform microwave spectroscopy and double resonance techniques, guided by new high-level CCSD(T) quantum-chemical calculations of its molecular structure. Rotational spectra of the two most stable isomers of $\ce{HOSOH}$, the putative ground state with $C\_2$ symmetry and the low-lying $C\_s$ rotamer, have been measured to high precision up to $\pu{71 GHz}$, allowing accurate spectroscopic parameters to be derived for both isomers. $\ce{HOSOH}$ may play a role in atmospheric and interstellar chemistry, and the present work provides the essential data to enable remote sensing and/or radioastronomical searches for these species. Spectroscopic characterization of $\ce{HOSOH}$ suggests that other transient intermediates in the oxidation of $\ce{SO2}$ to $\ce{H2SO4}$ may be amenable to laboratory detection as well.
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![GraphicalAbstract](https://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpcafh/2013/jpcafh.2013.117.issue-17/jp400742q/production/images/medium/jp-2013-00742q_0007.gif)


Most recently, using chemical trapping techniques, the additional three tautomers of sulfoxylic acid were identified and characterized (see scheme below; [ref.2](https://doi.org/10.1016/j.redox.2017.10.012)). These authors suggest that $\ce{HOSOH}$ may exhibit both nucleophilic and electrophilic reactivity, of which they attributed to interconversion of $\ce{HOSOH}$ between its tautomers (they used that phenomenon to trapped them). Theoretical calculations suggest that alcohol $16$ is the most stable, and peroxide $19$ is the least stable tautomer (see Scheme). 


[![tautomers of HOSOH](https://i.stack.imgur.com/IFgo3.jpg)](https://i.stack.imgur.com/IFgo3.jpg)


**References:**


1. Microwave Detection of Sulfoxylic Acid ($\ce{HOSOH}$): K. N. Crabtree, O. Martinez, L. Barreau, S. Thorwirth, M. C. McCarthy, *J. Phys. Chem. A*, **2013**, *117(17)*, 3608–3613.
2. Chemical trapping and characterization of small oxoacids of sulfur (SOS) generated in aqueous oxidations of $\ce{H2S}$: M. R. Kumar, P. J. Farmer, *Redox Biology*, **2018**, *14*, 485–491.


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