In which of the following combination of reagents precipitate is not formed.

Options

A. `Mn^(2+)(aq).+H_(2)O_(2)+NH_(3)" solution"`
B. `Al^(3+)(aq).+(NH_(4))_(2)S`
C. `Cr^(3+)(aq).+H_(2)O_(2)+NaOH" solution"`
D. `Fe^(2+)(aq).+Na_(2)O_(2)`

Answer

A

Explanation

HBr In dark follows markovnikov's addition (electrophilic addition) HBr in the presence of peroxide goes for anti-markovnikkov's product without any rearrangement.
HI follows markovnikov's addition in the presence or absence of peroxide.