Which of the following halides react(s) with `AgNO_(3(aq))` to give a precipitate that dissolves in `Na_(2)S_(2)O_(3(aq))`

Options

A. HCl
B. HF
C. HBr
D. HI

Answer

A, C, D

Explanation

HF does not gives any ppt. with `AgNO_(3)` since AgF is soluble in water. However, HCl, HBr and HI all react with `AgNO_(3)` to give first ppt. of the corresponding silver halide which dissolves in aqueous `Na_(2)S_(2)O_(3)` solution.
`{:(HCl + AgNO_(3) rarr underset("White ppt.")(AgCl) + HNO_(3)),(HBr + AgNO_(3) rarr underset("Pale yellow ppt.")(AgBr) + HNO_(3)),(HI + AgNO_(3) rarr underset("Yellow ppt.")(AgI) + HNO_(3)),(AgCl (or AgBr or AgI) + 2 Na_(2)S_(2) O_(3) rarr underset(("dissolves to gives colourless solution"))underset("Sod. argentothiosulphat")(Na_(3)[Ag(S_(2)O_(3))_(2)])+ NaCl (or NaBr or Nal)):}`