Question #966b5

1 Answer
Kaisha
May 15, 2017

See below.

Explanation:

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.

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