“…sulfite addition compounds, the sulfur is tetravalent. In view of the oxidizability of many tetravalent sulfur compounds, the ease of hydrolysis of sulfite esters, 16 and the fact that alkyl hydrogen sulfites (like sulfurous acid) are unknown, 1 would be expected to yield free sulfite or to behave like free sulfite when our equilibration solutions were quenched with acid before iodometric titration. Hence, when isobutyraldehyde is present in greater and greater excess over sulfite, the fraction of sulfite that is titratable should approach [!]/([!]…”