A metal complex having composition `[Cr(NH_(3))_(4)Br_(2)I]` was isolated in two forms (X) and (Y). Form (X) reacts with `AgNO_(3)` to give a pale yellow precipitate which is partially soluble in excess of `NH_(4)OH` whereas (Y) gives a greenish yellow precipitate which is insoluble in `NH_(4)OH`.
what is formula of X and Y?

Options

A. The formula of (X) and (Y) are `[Cr(NH_(3))_(4)BrI]Br" and "[Cr(NH_(3))_(3)Br_(2)I]NH_(3)` respectively
B. The formula of (X) and (Y) are `[Cr(NH_(3))_(4)BrI]Br" & "[Cr(NH_(3))_(4)Br_(2)]I` repectively
C. The formula of (X) and (Y) are both `[Cr(NH_(3))_(4)I]Br_(2)`
D. The formula of (X) and (Y) are `[Cr(NH_(3))_(2)IBr_(2)](NH_(3))_(2)`

Answer

b

Explanation

X has one `Br^(-)` ion outside the co-ordination sphere. Y has `I^(-)` outside the co-ordination sphere. Note AgBr is partially soluble in ammonia whereas AgI is insoluble.