CHEMISTRY · Multi-part · AP · Chemistry · Compound Structure and Properties · Compound Structure and Properties
Problem
The thiosulfate ion, S2O32−, is widely used in photographic fixing solutions and analytical titrations.
(a) Construct all nonequivalent Lewis structures for S2O32− that obey charge balance, allowing sulfur to exceed the octet when necessary.
(b) For each structure, compute the formal charge on every atom and rank the structures according to their expected relative importance in the resonance hybrid.
(c) Depict a resonance hybrid for S2O32− by showing partial S–O and S–S bond orders as well as partial charges.
(d) Using your resonance hybrid, predict which of the two sulfur atoms (the terminal "outer" S versus the "bridging" S attached to two other atoms) is more susceptible to attack by an electrophile, and justify your reasoning.