Question

The salt containing cupric ions are of:
I) Yellow colour
ii)Black colour
iii)Blue colour
iv)Colourless

Answer 1

iii will be correct ok

Answer 2

(iii) option is correct.

Given:

The salt containing cupric ions.

solution:

• cupric ion is represented as Cu2+

• Generally, Color of any element is exhibited by the presence of unpaired electrons or due to d-d transition.

here, the cupric ion is in +2 oxidation state.

the electronic configuration of Cu2+ is Cu2+=[Ar]3d9.

• we can see that the two electrons are removed from the outermost orbital, one from 4s and the other from 3d, to form cupric ions.

• The blue color is mainly exhibited due to the d-d transition studied in crystal field theory.

• crystal field theory:  electrons in d orbit are excited when a photon is placed on metal and electrons in d orbit jump to another d orbit with higher energy level so that the color is shown by absorbing the energy in the visible region.

hence, the blue color is exhibited.