Question #966b5

1 Answer
May 15, 2017


See below.


Test for #Cr^(3+)# is treating it with NaOH. It gives a grey-green precipitate which is soluble in excess NaOH to give a dark green solution.

Or you can treat it with aqueous #NH_3# where it forms a grey-green precipitate and insoluble in excess ammonia.

It dissolves in dilute HCl to form solutions containing #Cr^(2+)#. So it would be 3.