1) In the following reaction sequence in aqueous solution, the species X, Y and Z, respectively are $S_{2}O_3^{2-}\underrightarrow {Ag^{+}}$ $X (Clear. solution)$ $\underrightarrow {Ag^{+}}$ $Y (white. ppt)\underrightarrow {with.time}$ $Z (black.ppt)$ A) $[Ag(S_{2}O_{3})_{2}]^{3-}, Ag_{2}S_{2}O_{3}.Ag_{2}S$ B) $[Ag(S_{2}O_{3})_{3}]^{5-}, Ag_{2}S_{}O_{3}.Ag_{2}S$ C) $[Ag(S_{}O_{3})_{2}]^{3-}, Ag_{2}S_{2}O_{3}.Ag_{}$ D) $[Ag(S_{}O_{3})_{3}]^{3-}, Ag_{2}S_{}O_{4}.Ag_{}$ Answer: Option AExplanation:$2S_{2}O_3^{2-}+Ag^{+}\rightarrow [Ag (S_{2}O_{3})_{2}]^{3-} (Clear.solution)$ $[Ag(S_{2}O_{3})_{2}]^{3-}+3Ag^{+}\rightarrow 2 Ag_{2}S_{2}O_{3}( white.ppt)$ $Ag_{2}S_{2}O_{3}+H_{2}O\rightarrow Ag_{2}S(Black .ppt)+H_{2}SO_{4}$
