Which of the following produces violet colour with `FeCI_(3)` solution?

Which of the following acid produces violet colour with FeCl_(3) solution ?

Which of the following compounds produces a violet colour on addition of a few drops of FeCl_(3) solution?

Which of the following gives violet colour with neutral ferric chloride solution

Which of the following imparts violet colouration to the non-luminous flame of Bunsen burner ?

Which of the following imparts violet colouration to the Bunsen burner nonluminous flame ?