Which of the above mentioned reactions would yield white precipitate which on standing converts into black precipitate?

Which of the above mentioned reactions would yield white precipitate

1.	Which of the above mentioned reactions would yield white precipitate which on standing converts into black precipitate?
Answer» Solution :1 `Ag_(2)S_(2)O_(3) RARR Ag_(2)S darr` (BLACK) 2 `PbS_(2)O_(3) rarr PbS darr`(Black) 4 `Bi_(2)(S_(2)O_(3))_(3) rarr Bi_(2)S_(3)darr` (Black) 5 `Cu_(2)(S_(2)O_(3))rarr Cu_(2)Sdarr` (Black)