A metal gives two chlorides 'A' and 'B'.' A' gives a black precipitate with NH4 OH and 'B' gives white. 'B' gives a red precipitate on reaction with KI which is soluble in excess of KI. Identify 'A' and 'B', respectively.

Options

A. `Hg Cl _(2) and Hg _(2) Cl_(2)`
B. `Hg _(2) Cl _(2) and Hg Cl _(2)`
C. `Hg Cl _(2) and Hg OCl`
D. None of these

Answer

B

Explanation

A. is `Hg _(2) Cl and .B. Is Hg Cl _(2)`

`Hg Cl _(2) + 2 Kl to underset( Red) ( Hg l _(2)) + 2 KCl `
`H g l _(2) + 2 Kl to underset( "Soluble")( K _(2) H g l _(4))`