# Question #966b5

May 15, 2017

Test for $C {r}^{3 +}$ 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 $N {H}_{3}$ where it forms a grey-green precipitate and insoluble in excess ammonia.
It dissolves in dilute HCl to form solutions containing $C {r}^{2 +}$. So it would be 3.