explain why the addition of S2- ion to Cr(OH)3(s) does not result in the formation of Cr2S3(s)

Question

 The addition of S2- ion in to Fe(OH)2(s) results in the formation of FeS(s) 

Answer 1

The addition of S^2- ion to Cr(OH)₃(s) does not result in the formation of Cr₂S₃(s) because Cr₂S₃(s) is water soluble, it has to do with the d-orbital of Cr that can gain an electron to become half filled, it has a higher solubility constant. Also, Cr(OH)₃(s) has a higher rate of formation, it is less soluble, making it the more likely product to form.

 

The addition of S^2- ion in to Fe(OH)₂(s) results in the formation of FeS(s) because Fe has a d-orbital that is more than half filled, losing the effect of a half-filled d-orbital, making it insoluble in water; its rate of formation is high and rate of solubility is low.