Question

An ion $M^{2+}$, forms the complexes ${\left[M{\left(H_{2}O\right)}_6\right]}^{2+},{\left[M{\left(en\right)}_3\right]}^{2+}$ and ${\left[MB{r}_6\right]}^{4-}$, match the complex with the appropriate colour.

• A. Green, blue and red
• B. Blue, red and green
• C. Green, red and blue
• D. Red, blue and green

Answer 1

Answer: (A)

Green, blue and red

According to spectro chemical series,the order of strength of ligand is $en>H_{2}O>Br$ Strong ligand absorbs high energy wavelength and the order of energy of spectrum is $V>B>G>Y>O>R$

So,'en' absorbs green gives red colour ,$H_{2}O$ absorbs orange gives blue colour,$Br$ absorb red gives green compliment colour.

As ligand strength order is Br < $H_{2}O$ < en, so appeared colour will have opposite wavelength and order will be - green, blue, red.