Sodium thiosulphate, Na2S2O35H2O is used in photography to : — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Hypo is the common name for sodium thiosulfate (Na2S2O3). Step 2: Silver bromide (AgBr), though highly insoluble in water, dissolves in sodium thiosulfate due to a complexation reaction that creates a stable soluble complex. Step 3: The reaction is AgBr + 2Na2S2O3 -> Na3[Ag(S2O3)2] + NaBr. This complex contains the bis(thiosulfato)argentate(I) anion, [Ag(S2O3)2]^3-, matching option (d).