On the basis of the following observations made with aqueous solutions, how many of them have 6 secondary valencies ?
`{:(" Formula","Moles of AgCl precipitated per mole of the compounds with excess" AgNO_(3)),((a) PdCl_(2).4NH_(3)," "2),((b) NiCl_(2).6H_(2)O," "2),((c) PtCl_(4).2HCl," "0),((d) CoCl_(3).4NH_(3)," "1),((e) PtCl_(2).2NH_(3)," "0):}`

Answer

3

Explanation

`[Pd(NH_(3))_(4)]Cl_(2) " "[Ni(H_(2)O)_(6)]Cl_(2)`,
`H_(2)[PtCl_(6)]," " [Co(NH_(3))_(4)Cl_(2)]Cl`,
`[Pt(NH_(3))_(2)Cl_(2)]`