Question

Advanced Inorganic Chemistry

Outline a method for quantitatively analyzing [Cr(NH₃)₆](NO₃)₃ for its Cr and NH₃ content. (So, after the synthesis of Hexaamminechromium(III) Nitrate Using Liquid Ammonia / Na metal / CrCl_3, we need to quantitatively analyze the product for its Cr and NH₃)

Answer 1

The quantitative analysis of [Cr (NH3) 6 ] (NO3) 3 calls for an study over UV-visible spectrum of the CANARY YELLOW colored product synthesised.The UV-visible spectrum obtained for the diluted product should offer peak maxima at 304 , 351 , and 465 nm. The lower two energy observed absorptions arise from d-d transitions from A_2g to T_2g and A_2g to T_ig. ,It should be noted that as solutions of HNO3 (aq) are colorless, the NO3^- ion which dissociates in aqueous solutions from parent salt Hexaamine chromium (III) Nitrate does not give a visible absorption spectrum and in measurements taken from 250 nm in the UV region.A high - UV absorption for (NO3^- ) is not observed.The third observed peak at 304 nm is attributed to A_2g to T_ig  transition.