In black-and-white film developing, excess AgBr is removed from the film negative by ‘hypo', an aqueous solution of sodium thiosulfate (Na2S2O3), through formation of the complex ion Ag(S2O3)2^3-. Calculate the solubility of AgBr in (a)H2O (b) 1.0M hypo. Kf of Ag(S2O3)2^3- is 4,7 x 10^13 and Ksp AgBr is 5 x 10^-13.