Correct Answer - a
`underset((A))(BiCl_(3))+H_(2)Oto underset(("Redissolves in HCl"))underset((B))underset("White ppt.")(BiOCldarr)+2HCl`
`2BiCl_(3)+3H_(2)Stounderset((C))underset("black ppt.")(Bi_(2)S_(3))+6HCl`
`underset((A))(2BiCl_(3))+3H_(2)SO_(4)overset(Delta)toBi_(2)(SO_(4))_(3)+underset((D))(6HCl)`
`Hg_(2)(NO_(3))_(2)+2HCl to Hg_(2)Cl_(2) darr +2HNO_(3)`