Unexposed silver halides are removed from photographic film by reaction with sodium thiosulfate (Na2S2O3, called hypo) to form the complex ion; Ag(S2O3)2^3-. What mass of Na2S2O3 is required to prepare 1.00 L of a solution that will dissolve 1.00 g of AgBr by the formation of Ag(S2O3)2^3-? Show work.

Kf for Ag(S2O3)2^3- = 4.7e13

Ksp for AgBr = 7.7e-13

(hint: merge Ksp and Kf into one overall equation showing the dissolution of AgBr by thiosulfate to form bisthiosufatoargentate (I) complex ion and Br-.)